Omega-3 and -6 Fatty Acids Alter the Membrane Lipid Composition and Vesicle Size to Regulate Exocytosis and Storage of Catecholamines

The two essential fatty acids, alpha-linolenic acid and linoleic acid, and the higher unsaturated fatty acids synthesized from them are critical for the development and maintenance of normal brain functions. Deficiencies of these fatty acids have been shown to cause damage to the neuronal development, cognition, and locomotor function. We combined electrochemistry and imaging techniques to examine the effects of the two essential fatty acids on catecholamine release dynamics and the vesicle content as well as on the cell membrane phospholipid composition to understand how they impact exocytosis and by extension neurotransmission at the single-cell level. Incubation of either of the two fatty acids reduces the size of secretory vesicles and enables the incorporation of more double bonds into the cell membrane structure, resulting in higher membrane flexibility. This subsequently affects proteins regulating the dynamics of the exocytotic fusion pore and thereby affects exocytosis. Our data suggest a possible pathway whereby the two essential fatty acids affect the membrane structure to impact exocytosis and provide a potential treatment for diseases and impairments related to catecholamine signaling.

Antimicrobial and antibiofilm effects of essential fatty acids against clinically isolated vancomycin-resistant Enterococcus faecium

Introduction

Enterococcus faecium is a leading cause of hospital-acquired infections, which has become a serious public health concern. The increasing incidence of vancomycin-resistant E. faecium (VRE-fm) raises an urgent need to find new antimicrobial agents as a complement to traditional antibiotics. The study aimed to evaluate the antimicrobial and antibiofilm activity of essential fatty acids (EFAs) against VRE-fm, and further explore the molecular mechanism of the antibiofilm activity of EFAs.

Method

The microdilution broth method was used for antimicrobial susceptibility testing with traditional antibiotics and EFAs, including α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linoleic acid (LOA), γ-linolenic acid (GLA), and arachidonic acid (AA). The effect of EFAs on cell morphology of VRE-fm was investigated by scanning electron microscopy. The crystal violet method was used to evaluate the antibiofilm activities of EFAs against VRE-fm. Furthermore, the expression of biofilm-related genes (acm, atlA, esp, and sagA) of VRE-fm isolates under the action of GLA was analyzed using quantitative reverse transcription PCR (qRT-PCR) assay.

Results

VRE-fm isolates were highly resistant to most traditional antibiotics, only highly susceptible to quinupristin-dalfopristin (90.0%), tigecycline (100%), and linezolid (100%). EPA, DHA, and GLA exhibited excellent antimicrobial activity. The MIC50/90 of EPA, DHA, and GLA were 0.5/1, 0.25/0.5, and 0.5/1 mM, respectively. SEM imaging showed that strain V27 adsorbed a large number of DHA molecules. Furthermore, all EFAs exhibited excellent inhibition and eradication activities against VRE-fm biofilms. The biofilm inhibition rates of EFAs ranged from 45.3% to 58.0%, and eradication rates ranged from 54.1% to 63.4%, against 6 VRE-fm isolates with moderate biofilm formation ability. GLA exhibited remarkable antibiofilm activity against VRE-fm isolates. The qRT-PCR analysis showed that GLA could significantly down-regulate the expression of the atlA gene (P < 0.01) of VRE-fm.

Conclusion

DHA showed the strongest antibacterial activity, while GLA showed the strongest antibiofilm effect among the EFAs with antibacterial activity. Our novel findings indicate that the antibiofilm activity of GLA may be through down-regulating the atlA gene expression in VRE-fm. Therefore, DHA and GLA had the potential to be developed as therapeutic agents to treat infections related to multiple antimicrobial-resistant E. faecium.

Review: Effect of essential fatty acids and conjugated linoleic acid on the adaptive physiology of dairy cows during the transition period

Cows fed total mixed rations (silage-based) may not receive as much essential fatty acids (EFAs) and conjugated linoleic acids (CLAs) as cows fed pasture-based rations (fresh grass) containing rich sources of polyunsaturated fatty acids. CLA-induced milk fat depression allows dairy cows to conserve more metabolisable energy, thereby shortening the state of negative energy balance and reducing excessive fat mobilisation at early lactation. EFAs, particularly α-linolenic acid, exert anti-inflammatory and antioxidative properties, thereby modulating immune functions. Thus, combined EFA and CLA supplementation seems to be an effective nutritional strategy to relieve energy metabolism and to improve immune response, which are often compromised during the transition from late pregnancy to lactation in high-yielding dairy cows. There has been extensive research on this idea over the last two decades, and despite promising results, several interfering factors have led to varying findings, making it difficult to conclude whether and under what conditions EFA and CLA supplementations are beneficial for dairy cows during the transition period. This article reviews the latest studies on the effects of EFA and CLA supplementation, alone or in combination, on dairy cow metabolism and health during various stages around parturition. Our review article summarises and provides novel insights into the mechanisms by which EFA and/or CLA influence markers of metabolism, energy homeostasis and partitioning, immunity, and inflammation revealed by a deep molecular phenotyping.

Evaluation of supplemental fat sources and pre-farrow essential fatty acid intake on lactating sow performance and essential fatty acid composition of colostrum, milk, and adipose tissue

A total of 91 sows (Line 241, DNA Genetics) were used to evaluate the effects of supplemental fat sources and essential fatty acid intake on sow farrowing performance, litter growth performance, and essential fatty acid composition of colostrum, milk, and adipose tissue. At approximatelyday 107 of gestation, sows were blocked by body weight and parity, then allotted to 1 of 5 experimental treatments as part of a 2 × 2 + 1 factorial arrangement. Experimental diets were corn-soybean meal-based with a control diet that contained no added fat or diets with 3% added fat as either beef tallow or soybean oil, with consumption of the added fat diets starting on day 107 or 112 of gestation and fed until weaning. Thus, sows were provided low essential fatty acids (EFA; as linoleic and α-linolenic acid) without supplemental fat or with beef tallow or high EFA with soybean oil. Sows were provided approximately 2.8 kg/d of their assigned lactation diet pre-farrow and then provided ad libitum access after parturition. Sows consuming diets with beef tallow had greater lactation ADFI (fat source, P = 0.030), but lower daily linoleic acid (LA) and α-linolenic acid (ALA) intake than sows that consumed diets with soybean oil (fat source, P < 0.001). Supplemental fat sources providing either low or high EFA did not influence litter growth performance (fat source, P > 0.05). Sows fed diets with beef tallow did not influence the LA composition of colostrum; however, lactation diets with high EFA provided by soybean oil on day 107 of gestation increased colostrum LA concentration compared to providing diets on day 112 of gestation (fat source × time, P = 0.084; time, P < 0.001). Additionally, regardless of pre-farrow timing, ALA concentration of colostrum increased when sows consumed diets with soybean oil compared to beef tallow (fat source, P < 0.001). Both LA and ALA concentrations of milk at weaning were greater for sows that consumed diets with soybean oil compared to beef tallow (fat source, P < 0.001). Furthermore, concentrations of LA and ALA within adipose tissue were greater at weaning when sows consumed diets with high EFA compared to low EFA (fat source, P < 0.05). These responses suggest that providing dietary fat sources with high concentrations of EFA can increase backfat, colostrum, and milk LA and ALA. However, in this experiment, changes in colostrum and milk composition did not influence litter growth performance.

A Combination of Essential Fatty Acids, Panax Ginseng Extract, and Green Tea Catechins Modifies Brain fMRI Signals in Healthy Older Adults

OBJECTIVES

To assess the effects of a combination of omega 3 essential fatty acids, green tea catechins, and ginsenosides on cognition and brain functioning in healthy older adults.

DESIGN

Double-blind, placebo-controlled, crossover design randomized controlled trial with 26-day intervention phases and a 30-day washout period.

SETTING

The Institute for Dementia Research and Prevention at the Pennington Biomedical Research Center.

PARTICIPANTS

Ten independently-living, cognitively-healthy older adults (mean age: 67.3 + 2.01 years).

INTERVENTION

Daily consumption of an investigational product (trade name "Cerbella TM") consisting of an emulsified liquid combination of standardized fish oil, panax ginseng extract, and green tea catechins in a flavored base of lecithin phospholipids optimized to maximize bioavailability of the active ingredients.

MEASUREMENTS

Before and after supplementation with the investigational product or placebo, participants completed cognitive tests including the Mini Mental State Exam (MMSE), Stroop test, Digit Symbol Substitution Test (DSST), and Immediate and Delayed Recall tests, as well as functional magnetic resonance imaging (fMRI) during a standard cognitive task switching paradigm.

RESULTS

Performance on the MMSE, Stroop test, and DSST increased significantly over one month of supplementation with the investigational product (one-sample t tests, p<.05) although differences between these changes and corresponding changes during supplementation with placebo were not significant (two-sample t tests, p>.05). During supplementation with the investigational product, brain activation during task performance increased significantly more than during supplementation with placebo in brain regions known to be activated by this task (anterior and posterior cingulate cortex). Functional connectivity during task execution between task regions (middle frontal gyrus and anterior cingulate cortex) increased significantly during supplementation with the investigational product, relative to placebo. Functional connectivity during rest between task regions (precentral gyrus and middle frontal gyrus) and default mode network regions (medial frontal gyrus and precuneus) decreased during supplementation with the investigational product relative to placebo, suggesting greater segregation of task and rest related brain activity.

CONCLUSION

One-month supplementation with a combination of omega 3 essential fatty acids, green tea catechins, and ginsenosides was associated with suggestive changes in cognitive functioning as well as modification of brain activation and brain functional connectivity in cognitively healthy older adults.

Essentiality of arachidonic acid intake in murine early development

We previously reported the importance of long-chain polyunsaturated fatty acid (LC-PUFA (>C20)) intake, including arachidonic acid (ARA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), for growth. This follow-up study focuses on ARA using a novel artificial rearing model during the lactation period in delta-6-desaturase knockout (D6D-KO) mice. Newborn D6D-KO male mouse pups were separated from dams within 48 hours and fed artificial milks containing 18-C essential fatty acids (EFAs) (16-17% LA, 3.8-4.1% ALA) with or without 1.2% ARA. After weaning, mice were maintained on similar diets: 15% LA, 2.3-2.4% ALA with or without 1.9% ARA. As a reference group, new born wild type (WT) male mouse pups were maintained by artificial milk and diet containing LA and ALA without ARA. Aspects of brain function were measured behaviorally (motor activity and rota-rod test) when mice were age 9 weeks. Body weight in the KO-Cont group was significantly lower (approximately 30%) than in the WT-Cont group, but this decrease was ameliorated by providing ARA in the KO-ARA group. The motor activity and coordination in the KO-Cont group decreased markedly compared to the WT-Cont group. The KO-ARA group had a tendency toward deteriorated motor coordination, although the motor activity was significantly enhanced compared to the KO-Cont group. In KO-ARA group brains, the level of ARA was increased and DHA decreased compared to WT-Cont. These results suggest that intake of LA and ALA only is insufficient to support healthy growth, and that ARA is also required, at least during the lactation period. These findings also suggested that continued intake of relatively high levels of ARA and without supplemental DHA during development led to an increased motor activity above that of WT animals. These studies indicate that both ARA dose and proper combination with DHA must be delineated to define optimal growth and behavioral function.

Identification and signature profiles for pro-resolving and inflammatory lipid mediators in human tissue

Resolution of acute inflammation is an active process locally controlled by a novel genus of specialized pro-resolving mediators (SPM) that orchestrate key resolution responses. Hence, it is of general interest to identify individual bioactive mediators and profile their biosynthetic pathways with related isomers as well as their relation(s) to classic eicosanoids in mammalian tissues. Lipid mediator (LM)-SPM levels and signature profiles of their biosynthetic pathways were investigated using liquid chromatography-tandem mass spectrometry (LC-MS-MS)-based LM metabololipidomics. LM and SPM were identified using ≥6 diagnostic ions and chromatographic behavior matching with both authentic and synthetic materials. This approach was validated using the composite reference plasma (SRM1950) of 100 healthy individuals. Using targeted LM metabololipidomics, we profiled LM and SPM pathways in human peripheral blood (plasma and serum) and lymphoid organs. In these, we identified endogenous SPM metabolomes, namely, the potent lipoxins (LX), resolvins (Rv), protectins (PD), and maresins (MaR). These included RvD1, RvD2, RvD3, MaR1, and NPD1/PD1, which were identified in amounts within their bioactive ranges. In plasma and serum, principal component analysis (PCA) identified signature profiles of eicosanoids and SPM clusters. Plasma-SPM increased with omega-3 and acetylsalicylic acid intake that correlated with increased phagocytosis of Escherichia coli in whole blood. These findings demonstrate an approach for identification of SPM pathways (e.g., resolvins, protectins, and maresins) in human blood and lymphoid tissues that were in amounts commensurate with their pro-resolving, organ protective, and tissue regeneration functions. LM metabololipidomics coupled with calibration tissues and physiological changes documented herein provide a tool for functional phenotypic profiling.

Metabolic and endocrine effects of long-chain versus essential omega-3 polyunsaturated fatty acids in polycystic ovary syndrome

The objective of the study was to compare the effects of essential vs long-chain omega (n)-3 polyunsaturated fatty acids (PUFAs) in polycystic ovary syndrome. In this 6-week, prospective, double-blinded, placebo (soybean oil)-controlled study, 51 completers received 3.5 g n-3 PUFA per day (essential PUFA from flaxseed oil or long-chain PUFA from fish oil). Anthropometric variables, cardiovascular risk factors, and androgens were measured; oral glucose tolerance test (OGTT) and frequently sampled intravenous GTT (IVGTT) were conducted at baseline and 6 weeks. Between-group comparisons showed significant differences in serum triglyceride response (P = .0368), whereas the changes in disposition index also tended to differ (P = .0621). When within-group changes (after vs before intervention) were considered, fish oil and flaxseed oil lowered serum triglyceride (P = .0154 and P = .0176, respectively). Fish oil increased glucose at 120 minutes of OGTT (P = .0355), decreased the Matsuda index (P = .0378), and tended to decrease acute insulin response during IVGTT (P = .0871). Soybean oil increased glucose at 30 (P = .0030) and 60 minutes (P = .0121) and AUC for glucose (P = .0122) during OGTT, tended to decrease acute insulin response during IVGTT (P = .0848), reduced testosterone (P = .0216), and tended to reduce sex hormone-binding globulin (P = .0858). Fasting glucose, insulin, adiponectin, leptin, or high-sensitivity C-reactive protein did not change with any intervention. Long-chain vs essential n-3 PUFA-rich oils have distinct metabolic and endocrine effects in polycystic ovary syndrome; and therefore, they should not be used interchangeably.

Dietary fish and evening primrose oil with vitamin E effects on semen variables in cockerels

Our aim was to determine the effect of n-3 (2%, wt/wt, fish oil rich diet) and n-6 (2%, wt/wt, evening primrose oil rich diet) fatty acid dietary supplementation and their combination with two concentrations of vitamin E (40 vs 200 mg/kg) on semen variables and on fatty acid and vitamin E profiles of spermatozoa in broiler breeders at 32, 42 and 52 weeks of age. The inclusion of fish oil in the cockerel diets increased the docosahexaenoic acid proportion in the sperm phospholipid fraction, which was almost threefold higher compared to the other two groups irrespective of vitamin E supplementation. In contrast, an increase in the proportion of total n-6 polyunsaturates, mainly 22:4n-6, was observed in the evening primrose oil group compared to the control only when the dietary content of vitamin E was increased to 200 mg/kg. Sperm concentration was decreased in the fish and evening primrose oil groups if vitamin E was 40 mg/kg, but such an effect was prevented in the fish, not the evening primrose oil group, by increasing the vitamin E to 200 mg. The proportion of motile spermatozoa was improved by the increased supplementation of vitamin E in all oil treatments.

Cytoprotective effects of phenolic antioxidants and essential fatty acids in human blood monocyte and neuroblastoma cell lines: surrogates for neurological damage in vivo

BACKGROUND

Oxidative stress is implicated in the development of a range of neurological diseases. There is increasing interest in the neuroprotective efficacy of antioxidants in modulating such processes with at least one polyphenolic being tested as a prophylactic in Alzheimer's disease. Beneficial effects of adjunctive n-3 polyunsaturated fatty acids with combined intakes of vitamin C and E on both the positive and negative symptoms of schizophrenia have been reported. Robust in vitro systems are desirable, enabling a mechanistic investigation of the molecular mechanisms underpinning such effects and identification of further potentially efficacious nutraceuticals.

MATERIALS AND METHOD

A comparative study employing a human lymphoblastoid cell line derived from a subject with early onset schizophrenia, a neuroblastoma IMR-32 cell line and the histiocytic lymphoma U937 cell line was undertaken. The cytoprotective effects of two phenols in affording protection to cellular DNA from an oxidative challenge were assessed in untreated and fatty acid treated cell lines.

RESULTS AND CONCLUSION

Marked differences in the uptake of fatty acids by the cell types were found and the IMR-32 cell line was most susceptible to the oxidant challenge. Hydroxytyrosol gave significant cytoprotection in all three-cell lines and this possible neuroprotective efficacy warrants further investigation, both in vitro and in vivo.

Diet and Gene Expression: Delta-5 and Delta-6 Desaturases in Healthy Chinese and European Subjects

AIM

To compare the composition of fatty acids (FAs) in diet, and the expression of delta-6 desaturase (D6D) and delta-5 desaturase (D5D) genes in peripheral blood mononuclear cells (PBMCs) between Chinese and Europeans.

METHODS

Three-day dietary records from 20 subjects from Beijing, China (n = 10) and Kent, UK (n = 10) were analysed. Expression of PBMC D6D and D5D genes of the subjects was determined using RT-PCR.

RESULTS

The dietary intake of Chinese subjects contained less saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs), but more essential fatty acids (EFAs) than that of Europeans. Levels of expression of PBMC D6D and D5D genes of Chinese subjects were significantly lower than those of Europeans. A significant positive correlation was found between dietary intake of total SFAs and total MUFAs and expression of PBMC D6D and D5D genes, but a significant negative correlation between dietary intake of linoleic acid (LA) and alpha-linolenic acid (LNA) and the expression of PBMC D6D and D5D genes.

CONCLUSION

Intake of high SFAs and MUFAs appears to increase expression of PBMC D6D and D5D genes, whilst high EFAs intake appears to decrease expression of PBMC D6D and D5D genes. A follow-up study of the expression of D6D and D5D genes in Chinese who live in European countries with high SFA and MUFA diets would be of interest.

Protective effects of omega-3 essential fatty acids against formaldehyde-induced neuronal damage in prefrontal cortex of rats

The aim of this study was to examine the neurotoxicity of formaldehyde on prefrontal cortex and the protective effects of omega-3 essential fatty acids against these toxic effects. For this purpose, 21 male Wistar rats were divided into three groups. The rats in group I comprised the controls, while the rats in group II were injected every other day with formaldehyde (FA). The rats in group III received omega-3 fatty acids daily while exposed to formaldehyde. At the end of the 14-day experimental period, all rats were killed by decapitation. The brains of the rats were removed and the prefrontal cortex tissues were obtained from all brain specimens. Some of the prefrontal cortex tissue specimens were used for determination of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels. The remaining prefrontal cortex tissue specimens were used for light microscopic and immunohistochemical evaluation. The levels of SOD and GSH-Px were significantly decreased, and MDA levels were significantly increased in rats treated with formaldehyde compared with those of the controls. Furthermore, in the microscopic examination of this group, formation of apoptotic bodies, pycnotic cells, and apoptotic cells including nuclear fragmentation and membrane budding were observed. However, increased SOD and GSH-Px enzyme activities, and decreased MDA levels were detected in the rats administered omega-3 fatty acids while exposed to formaldehyde. Additionally, cellular damage caused by formaldehyde was decreased, and structural appearance was similar to that of the control rats in this group. The biochemical and histological findings observed in all groups were also confirmed by immunohistochemical evaluation. It was determined that formaldehyde-induced neuronal damage in prefrontal cortex was prevented by administration of omega-3 essential fatty acids.

Supplementation with flax oil and vitamin C improves the outcome of Attention Deficit Hyperactivity Disorder (ADHD)

Considerable clinical and experimental evidence now supports the idea that deficiencies or imbalances in certain highly unsaturated fatty acids may contribute to a range of common developmental disorders including Attention Deficit Hyperactivity Disorder (ADHD). Few intervention studies with LCPUFA supplementation have reported inconsistent and marginal results. This pilot study evaluates the effect of alpha linolenic acid (ALA)-rich nutritional supplementation in the form of flax oil and antioxidant emulsion on blood fatty acids composition and behavior in children with ADHD. Post-supplementation levels of RBC membrane fatty acids were significantly higher than pretreatment levels as well as the levels in control. There was significant improvement in the symptoms of ADHD reflected by reduction in total hyperactivity scores of ADHD children derived from ADHD rating scale.

Evening primrose oil effects on osteoclasts during tooth movement

This study was conducted to investigate the influence of supplemented evening primrose oil (EPO) on osteoclast expression during experimental tooth movement in rats. Forty-eight 10-week-old male Sprague-Dawley rats were divided into experimental and control groups. Animals in the experiment group were fed a 7.25 g/kg daily dose of EPO orally by gastric intubation for 20 days before orthodontic tooth movement. The animals in the control group received an equivalent volume of distilled water by the same method. On day 21, a 40-g mesial tipping force was applied to the maxillary right first molar of each rat. After loading, six animals in each group were sacrificed on days 0, 3, 7, and 14 with the appliance in situ. On day 3, the number of osteoclasts on the appliance side of the experimental group was significantly increased compared with the control group (P < .05). On day 7, the number of osteoclasts on the non-appliance side of the experimental group was significantly increased compared with the control group (P < .05). This study indicates that oral administration of EPO can increase the number of osteoclasts and may accelerate orthodontic tooth movement.

Dietary intake of essential and long-chain polyunsaturated fatty acids in pregnancy

The dietary intake of EFA and long-chain PUFA (LCPUFA) by women with (n = 14) and without (n = 31) gestational diabetes mellitus (GDM) was determined by repeated 24-h recalls. Women with GDM consumed significantly more energy as fat compared with women who had uncomplicated pregnancies; absolute dietary fat did not differ. Dietary n-3 LCPUFA was substantially lower than the current recommendation for pregnancy, whereas intake of saturated FA (SFA) exceeded it. We conclude that replacing dietary sources of SFA with those of EFA and LCPUFA, especially n-3 LCPUFA, would benefit the dietary fat profiles of all pregnant women.

Essential fatty acids and phospholipase A2 in autistic spectrum disorders

A health questionnaire based on parental observations of clinical signs of fatty acid deficiency (FAD) showed that patients with autism and Asperger's syndrome (ASP) had significantly higher FAD scores (6.34+/-4.37 and 7.64+/-6.20, respectively) compared to controls (1.78+/-1.68). Patients with regressive autism had significantly higher percentages of 18:0,18:2n-6 and total saturates in their RBC membranes compared to controls, while 24:0, 22:5n-6, 24:1 and the 20:4n-6/20:5n-3 ratio were significantly higher in both regressive autism and ASP groups compared to controls. By comparison, the 18:1n-9 and 20:4n-6 values were significantly lower in patients with regressive autism compared to controls while 22:5n-3, total n-3 and total dimethyl acetals were significantly lower in both regressive autism and ASP groups compared to controls. Storage of RBC at -20 degrees C for 6 weeks resulted in significant reductions in highly unsaturated fatty acid levels in polar lipids of patients with regressive autism, compared to patients with classical autism or ASP, or controls. Patients diagnosed with both autism and ASP showed significantly increased levels of EPA ( approximately 200%) and DHA ( approximately 40%), and significantly reduced levels of ARA ( approximately 20%), 20:3n-6 and ARA/EPA ratio in their RBC polar lipids, when supplemented with EPA-rich fish oils, compared to controls and non-supplemented patients with autism. Patients with both regressive autism and classical autism/Asperger's syndrome had significantly higher concentrations of RBC type IV phospholipase A2 compared to controls. However, patients with autism/ASP, who had taken EPA supplements, had significantly reduced PLA2 concentrations compared to unsupplemented patients with classical autism or ASP.

The possible role of essential fatty acids in the pathophysiology of malnutrition: a review

Biochemical evidence of essential fatty acid deficiency (EFAD) may exist in protein-energy malnutrition (PEM). EFAD is characterised by low 18:2omega6, often in combination with low 20:4omega6 and 22:6omega3, and high 18:1omega9 and 20:3omega9. Some PEM symptoms, notably skin changes, impaired resistance to infections, impaired growth rate and disturbed development may at least partly be explained by EFAD. One or more of the following factors could induce EFAD in PEM: low EFA intake, poor lipid digestion, absorption, transport, desaturation and increased EFA beta-oxidation and peroxidation. EFAD may perpetuate itself by decreasing lipid absorption and transport, and aggravate PEM by impairing nutrient absorption and dietary calorie utilisation. Micronutrient deficiencies may contribute to the impaired EFA bioavailability and metabolism. Nutritional rehabilitation strategies in PEM may consider adequate intakes of EFA and micronutrients, e.g. by promoting breastfeeding. More research is required to gain detailed insight into the role of EFAD in PEM.

Effects of eicosatrienoic acid (20:3 n-9, Mead's acid) on some promalignant-related properties of three human cancer cell lines

The essential fatty acid deficiency (EFAD) is a metabolic condition related to cancer development. We studied the effect of eicosapentaenoic acid (EPA, 20:5 n-3) and eicosatrienoic acid (ETA, 20:3 n-9), an essential fatty acid (EFA) and non-EFA respectively, on tumour cells parameters linked to tumour progression and metastases. Human tumour cell lines (T-24 from urothelium, MCF-7 from breast and HRT-18 from colon) were used. EPA showed an anti-proliferative effect on the three lines. ETA showed the following effects: in T-24, the lipid peroxidation was decreased and E-cadherin was undetectable; in MCF-7, increased E-cadherin expression enhanced the lipid peroxidation and decreased cell proliferation; on HRT-18, the E-cadherin expression and lipid peroxidation diminished, whereas cell proliferation was increased. In conclusion, EFA (20:5 n-3) exhibited beneficial effects, whereas unusual ETA showed an opposite effect on some tumour parameters. The possible riskiness of EFA-deprivation, along with the potential of EFA as natural nutrapeutic products for human tumour prevention and treatment, makes EFA worthy of further consideration.

Effects of different dietary oils on inflammatory mediator generation and fatty acid composition in rat neutrophils

Virgin olive oil (VOO) compared with fish oil (FO) and evening primrose oil (PO) on the ability of stimulated leukocytes to produce inflammatory mediators was investigated in rats. Weaned Wistar rats were fed a basal diet (BD) (2% by weight of corn oil) or diets containing 15% by weight of VOO, PO, or FO. After 8 weeks, glycogen-elicited peritoneal polymorphonuclear leukocytes, mainly neutrophils, were isolated. The calcium-ionophore stimulated neutrophils (2.5 x 10(6) cells/mL) obtained from rats fed the different oils produced a higher release of lysosomal enzymes (beta-glucuronidase, lysozyme, and myeloperoxidase [MPO]) compared with those fed BD. The production of reactive oxygen species (ROS) in response to the stimulant, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), by neutrophils from the VOO group (15.44 nmol of O(2)(-) and 6.56 nmol of H(2)O(2)) was similar to the BD group (12.01 nmol O(2)(-) and 8.49 nmol H(2)O(2)) and significantly lower than the PO (20.90 nmol O(2)(-) and 10.84 nmol H(2)O(2)) and FO (20.93 nmol O(2)(-) and 12.79 nmol H(2)O(2)) groups. The cyclooxygenase-derived eicosanoid production was reduced by the lipid enrichment of the diets. Whereas the generation of prostaglandin E(2) (PGE(2)) was significantly decreased in VOO (5.40 ng/mL), PO (4.95 ng/mL), and FO (1.44 ng/mL) groups compared with BD (8.19 ng/mL), thromboxane B(2) (TXB(2)) reduction was especially significant in neutrophils from the FO diet group (14.67 ng/mL compared with 26.69 ng/mL from BD). These experimental data suggest that FO and PO, as well as VOO, could be considered a valuable strategy in preventing the generation of some inflammatory mediators.

Caspase-independent apoptosis induced by evening primrose extract in Ehrlich ascites tumor cells

We previously demonstrated that evening primrose extract (EPE) induced apoptosis in Ehrlich ascites tumor cells, while mouse embryo fibroblast cells (NIH3T3) used as a normal cell model, showed no effect of cell viability by treatment of EPE. Furthermore, our results demonstrated the rapid increase in intracellular peroxides levels, loss of mitochondrial membrane potential and the release of cytochrome c to cytosol, suggesting that the rapid increase in intracellular peroxides levels after addition of EPE triggers off induction of apoptosis. In this study, we identified that EPE elicited the translocation of Bax to mitochondria and apoptosis-inducing factor (AIF) to nuclei, but no activation of caspase-3-like protease. We also demonstrated that the rapid EPE-induced increase in hydrogen peroxide levels caused the translocation of Bax to mitochondria, and then mitochondrial cytochrome c was released. One of the main consequences of mitochondrial cytochrome c release is the activation of caspase-3. However, no caspase-3 activation was observed. On the other hand, AIF was translocated from mitochondria to nuclei. The EPE-induced translocation of AIF was suppressed with the addition of catalase, suggesting that the rapid intracellular peroxide levels after addition of EPE triggers off induction of apoptosis, which is AIF-mediated and caspase-independent.

Potential role of dietary omega-3 essential fatty acids on some oxidant/antioxidant parameters in rats' corpus striatum

Omega-3 (omega-3) is an essential fatty acid (EFA) found in large amounts in fish oil. It contains eicosapentaenoic acid and docosahexaenoic acid (DHA). DHA is one of the building structures of membrane phospholipids of brain and necessary for continuity of neuronal functions. Evidences support the hypothesis that schizophrenia may be the result of increased reactive oxygen species mediated neuronal injury. Recent reports also suggest the protective effect of omega-3 EFA against neuropsychiatric disorders including schizophrenia. This study proposed to assess the changes in antioxidant enzyme and oxidant parameters in the corpus striatum (CS) of rats fed with omega-3 EFA diet (0.4g/kg/day) for 30 days. Eight control rats and nine rats fed with omega-3 were decapitated under ether anesthesia, and CS was removed immediately. Thiobarbituric acid-reactive substances (TBARS) and nitric oxide (NO) levels as well as total superoxide dismutase (t-SOD) and xanthine oxidase (XO) enzyme activities in the CS were measured. Rats treated with omega-3 EFA had significantly lower values of TBARS (P<0.001), NO (P<0.002) and XO (P<0.005) whereas higher values of t-SOD enzyme activity (P<0.002) than the control rats. These results indicate that omega-3 EFA rich fish oil diet reduces some oxidant parameters in CS. This may be revealed by means of reduced CS TBARS levels as an end product of lipid peroxidation of membranes in treated rats. Additionally, reduced XO activity and NO levels may support this notion. On the other hand, although the mechanism is not clear, omega-3 EFA may indirectly enhance the activity of antioxidant enzyme t-SOD. Taken together, this preliminary animal study provides strong support for a therapeutic effect of omega-3 EFA supplemented to classical neuroleptic regimen in the treatment of schizophrenic symptoms and tardive dyskinesia.

Effects of essential fatty acids on mediators of mast cells in culture

The objective of this study was to investigate the effects of alpha-linolenic acid (18:3n-3) and linoleic acid (18:2n-6) on the fatty acid composition and the activity and release of mast cell mediators in the canine mastocytoma cell line C2. Cells were cultured in Dulbecco's modified Eagle's medium mixed with 50% Ham's F12 (containing linoleic acid 0.14 micro M). The basic medium (DEH) was supplemented with 0.14 micro M alpha-linolenic acid. 14.0 micro M alpha-linolenic acid (DEH-n-3) or 14.0 micro M linoleic acid (DEH-n-6) was added. Eight days after culturing of C2 in DEH-n-3 we measured elevated levels of n-3 fatty acids up to 22:3. The tryptase activity and the stimulated PGE2 production and histamine release were reduced. In contrast, after culturing of C2 in DEH-n-6 we determined elevated levels of n-6 fatty acids up to 20:3, increased tryptase activity and stimulated histamine release. Thus 18:3n-3 has anti-inflammatory effects in cultured canine mastocytoma cells.

Energy vs. essential fatty acids: what do scallop larvae (Argopecten purpuratus) need most?

Larvae of the Chilean-Peruvian scallop Argopecten purpuratus were fed a Dunaliella tertiolecta diet (Dun-diet) supplemented with lipid emulsions, rich in 20:5n-3 (EmEPA), 22:6n-3 (EmDHA) or in saturated fatty acids (EmCOCO). A mixed algal diet of Isochrysis galbana (T-iso) and Chaetoceros neogracile served as a positive control (St-diet). Lipid supplementation to the Dun-diet improved the larval growth and increased the percentage of eyed larvae significantly, compared to the non-supplemented Dun-diet because of the extra energy supplied and not because of its fatty acid composition. No significant differences were observed between supplementation with EmEPA, EmDHA or EmCOCO. A mixture of 20% EmEPA+20% EmDHA (40% EmHUFA) was more efficient in raising the total lipid content in larvae than 40% EmCOCO. Both emulsions increased the triacylglycerol content in larvae compared to the non-supplemented Dun-diet. The best result, however, was obtained with the St-diet, probably because of a more suitable 18:2n-6/18:3n-3 ratio and a higher level of arachidonic acid. A positive relationship between the 18:2n-6/18:3n-3 ratio and the larval performance was found. No significant difference was observed in post-settlement larval size or percentage of metamorphosed larvae between the St-diet and the St-diet supplemented with 20% EmHUFA or 20% EmCOCO. The metamorphosed larvae had a constant DHA/EPA ratio of 3.7, independent from the diet, which suggested a metabolic control of the two fatty acids and a species-dependency of the ratio.

Individual fatty acids influence cultured human liver cells differently when compared to plant oils

Most work to date using fatty acids and cultured cells has concentrated on single fatty acids, yet cells in vivo are exposed to fatty acid combinations in the form of triacylglycerols and phosphoglycerides. We have quantitated the influence of the individual fatty acids that make up three plant oils, as well as the plant oils themselves, on the growth of normal and transformed human liver cell lines. The effects of the individual fatty acids were then combined in proportion to their concentration in each plant oil and compared to the effects of the intact oils. The oils initially induced synergistic effects with low concentrations, but with high concentrations competitive effects were shown, when compared to the combined effects of the individual fatty acids.

Botanicals and dietary supplements in diabetic peripheral neuropathy

BACKGROUND

Many persons use botanicals and dietary supplements for chronic conditions that do not respond to traditional Western medications. Tricyclic antidepressants, a common treatment option for diabetic neuropathy, can have many side effects and are a poor choice in certain populations (eg, the elderly). As such, patients might turn to botanicals and dietary supplements, not realizing that these products are not well regulated.

METHODS

This article reviews botanicals and dietary supplements that have been involved in randomized controlled trials (RCTs) for diabetic neuropathy. We searched MEDLINE for English-language literature dating from 1966 to April 2001 using the following subject headings: (1) diabetes and botanical, herb, and supplement, (2) neuropathy and botanical, herb, and supplement, and (3) diabetic neuropathy and botanical, herb, and supplement.

RESULTS

Our search found agents that might improve symptoms of neuropathy (eg, evening primrose oil, alpha-lipoic acid, capsaicin) without affecting glucose control. Botanicals and dietary supplements involved in only one RCT or associated with little clinical benefit were reviewed in brief.

CONCLUSIONS

Evening primrose oil, alpha-lipoic acid, and capsaicin have received the greatest attention for their use in diabetic neuropathy, but further studies are needed to confirm their efficacy. Patients using these products need to be informed of potential drug interactions and side effects.

Maternal and umbilical fatty acid status in relation to maternal diet

The aim of this study was to describe the dietary fat intake during pregnancy and to study the relationship between the intake of polyunsaturated fatty acids (PUFAs) and the fatty acid composition of maternal and umbilical plasma phospholipids (PLs) and cholesterol esters (CEs) at delivery. In addition, the contribution of food groups to the intake of total fat and fatty acids in the diet was quantified.Maternal and umbilical blood samples were collected at delivery from 30 healthy pregnant women. The women completed a food frequency questionnaire during the first and third trimesters. The total fat intake during pregnancy is 85 (SD 24) g/day. The mean intake of saturated fatty acids (SFAs) is 33.4 g/day, of monounsaturated fatty acids (MUFAs) 28.6 g/day and of PUFA 15.2 g/day. Major sources of fat, MUFA and PUFA are fats, oils and sauces. Major sources of SFA are meat and poultry followed by cheese and eggs. Meat and poultry contribute the most to the intake of 20:4n-6 whereas fish is the major source of 20:5n-3 (EPA) and 22:6n-3 (docosahexaenoic acid (DHA)) in the diet. Linoleic acid, EPA and DHA (w%) in PL of maternal plasma are positively related to the intake of these fatty acids during pregnancy. No association is found between the maternal intake of the two parent essential fatty acids (18:2n-6 and 18:3n-3) and their fraction in umbilical PL or CE. EPA and the sum of n-6 fatty acids (w%) in umbilical plasma PL are positively correlated with the dietary intake of these fatty acids.

Constituents in evening primrose oil with radical scavenging, cyclooxygenase, and neutrophil elastase inhibitory activities

Cold-pressed, non-raffinated evening primrose oil was found to contain lipophilic radical scavengers. A highly enriched fraction of these compounds could be obtained from the oil by extraction with aqueous ethanol and subsequent liquid-liquid partitioning with petroleum. LC-DAD-MS analysis revealed that the fraction contained three aromatic compounds with identical UV and ESI-MS spectra. The compounds were isolated by RP-HPLC and their structures established by chemical and spectroscopic means as 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid. The morolic acid derivative was a new compound. The three esters exhibited pronounced radical scavenging activity against the stable 2,2-diphenyl-1-picrylhydrazyl radical and were potent inhibitors of neutrophil elastase and cyclooxygenase-1 and -2 in vitro. Commercial samples of evening primrose oils contained only traces of these lipophilic antioxidants.

The effect of gamma-linolenic acid on plasma and membrane lipids and renal prostaglandin synthesis in older subjects

Senescence is associated with a decreased activity of enzyme delta-6 desaturase, which converts linoleic acid to gamma-linolenic acid. This enzymatic defect may alter the composition of plasma and membrane lipids, and influences the biosynthesis of renal prostaglandins. Exogenous supplementation of GLA during 3 months increases the plasma level of dihomo-gamma-linolenic acid (p < 0.002), and to a smaller degree, the level in erythrocyte membrane lipids. This treatment was associated with a beneficial reduction of cardiovascular risk factors (arterial hypertension, total cholesterol, apolipoprotein B, HDL-cholesterol, apolipoprotein A-I) and the renal function has become stable reached. Epogam treatment also increased the biosynthesis of renal prostaglandins, especially that of prostaglandin E2, which has a vasodilatory effect on vessel walls and reduces the elevated blood pressure.

CONCLUSION

Dietary supplementation of essential fatty acids such as gamma-linolenic acid to old subjects has beneficial effect on their health condition. (Tab. 6, Fig. 5, Ref. 37.)

Effects of diabetes and evening primrose oil treatment on responses of aorta, corpus cavernosum and mesenteric vasculature in rats

Diabetes causes endothelial dysfunction, with deleterious effects on nitric oxide (NO) mediated vasodilatation. However, in many vessels other local vasodilators such as endothelium-derived hyperpolarizing factor (EDHF), prostacyclin, epoxides or endocannabinoids are also important. Several of these factors may be derived from omega-6 essential fatty acids via arachidonate metabolism. Diabetes inhibits this pathway, a defect that may be bypassed by diets enriched with omega-6 gamma-linolenic acid-containing oils such as evening primrose oil (EPO). The aim was to examine the effects of preventive EPO treatment on endothelium-dependent and neurally mediated vasorelaxation. Diabetes was induced by streptozotocin in rats; duration was 8 weeks. Vascular responses were examined in vitro on thoracic aorta, corpus cavernosum and perfused mesenteric bed preparations. Diabetes caused 25% and 35% deficits, respectively, in aorta and corpus cavernosum NO-mediated endothelium-dependent relaxation to acetylcholine that were largely unaffected by EPO treatment. Moreover, a 44% reduction in maximum corpus cavernosum vasorelaxation to nitrergic nerve stimulation was not prevented by EPO. However, for the mesenteric vascular bed, a 29% diminution of responses to acetylcholine, mediated by both NO and EDHF, was 84% attenuated by EPO treatment. When the EDHF component was isolated during NO synthase inhibition, a 76% diabetic deficit was noted. This was completely prevented by EPO treatment, which also caused supernormal EDHF responses in nondiabetic rats. EPO treatment prevented the development of deficits in endothelium-dependent relaxation in diabetic rats. Effects were particularly marked on the resistance vessel EDHF system, which may have potential therapeutic relevance for diabetic microvascular complications.

Maternal dietary intake of essential fatty acids affects adipose tissue growth and leptin mRNA expression in suckling rat pups

We have previously shown that maternal intake of essential fatty acids during late gestation and lactation affects the level of serum leptin in pups. The aim of the present study was to investigate the effect of dietary essential fatty acids on leptin content in the milk of rat dams and leptin expression in white adipose tissue of pups during the suckling period. During late gestation and throughout lactation, rats were fed a control or an essential fatty acid-deficient (EFAD) diet. Milk of the EFAD dams contained more saturated and less polyunsaturated fatty acids compared with the control dams. Milk leptin levels were higher in the EFAD dams than in the control dams at 3 wk of lactation. The weight of inguinal white adipose tissue depots and the serum leptin levels of the EFAD pups were significantly lower than in the control pups during the whole suckling period. In addition, semiquantitative reverse transcriptase-PCR analysis of leptin mRNA levels in inguinal white adipose tissue showed a reduction in the EFAD pups compared with the control pups at 3 wk of age. We conclude that maternal dietary essential fatty acid intake affects serum leptin levels in pups by regulating both the amount of adipose tissue and the leptin mRNA expression.

A double-blind, randomized, placebo-controlled trial of essential fatty acid supplementation in the maintenance of remission of ulcerative colitis

BACKGROUND

Essential fatty acid supplementation has been found to ameliorate certain chronic inflammatory diseases. This effect is thought to be mediated through the modulation of eicosanoid synthesis. Pro-inflammatory eicosanoids have been implicated in ulcerative colitis.

AIM

To investigate the possible therapeutic benefit of essential fatty acids in quiescent ulcerative colitis to reduce the frequency of disease relapse.

METHODS

A randomized, double-blind, placebo-controlled study was performed with a treatment duration of 12 months. Patients with quiescent disease received either trial medication (gamma-linolenic acid, 1.6 g, eicosapentaenoic acid, 270 mg, and docosahexaenoic acid, 45 mg, per day) or placebo (sunflower oil, 500 mg/day). The primary end-point was disease activity, assessed by a previously validated clinical index, sigmoidoscopic appearance and histology.

RESULTS

Sixty-three patients were randomized, 31 to receive essential fatty acid treatment and 32 to receive placebo. Disease relapse rates were similar at 12 months (placebo, 38%; essential fatty acids, 55%), as were changes in sigmoidoscopic grade from baseline.

CONCLUSIONS

The supplementation of the diet with this combination of essential fatty acids does not prolong the period of disease remission of ulcerative colitis.

Essential fatty acids given from conception prevent topographies of motor deficit in a transgenic model of Huntington's disease

Transgenic R6/1 mice incorporate a human genomic fragment containing promoter elements exon 1 and a portion of intron 2 of the Huntingtin gene responsible for Huntington's disease. They develop late-onset neurological deficits in a manner similar to the motor abnormalities of the disorder. As essential fatty acids are phospholipid components of cell membranes which may influence cell death and movement disorder phenotype, R6/1 and normal mice were randomised to receive a mixture of essential fatty acids or placebo on alternate days throughout life. Over mid-adulthood, topographical assessment of behaviour revealed R6/1 transgenics to evidence progressive shortening of stride length, with progressive reductions in locomotion, elements of rearing, sniffing, sifting and chewing, and an increase in grooming. These deficits were either not evident or materially diminished in R6/1 transgenics receiving essential fatty acids. R6/1 transgenics also showed reductions in body weight and in brain dopamine D(1)-like and D(2)-like quantitative receptor autoradiography which were unaltered by essential fatty acids.These findings indicate that early and sustained treatment with essential fatty acids are able to protect against motor deficits in R6/1 transgenic mice expressing exon 1 and a portion of intron 2 of the Huntingtin gene, and suggest that essential fatty acids may have therapeutic potential in Huntington's disease.

Dietary essential fatty acids and brain function: a developmental perspective on mechanisms

Brain development is a complex interactive process in which early disruptive events can have long-lasting effects on later functional adaptation. It is a process that is dependent on the timely orchestration of external and internal inputs through sophisticated intra- and intercellular signalling pathways. Long-chain polyunsaturated fatty acids (LCPUFA), specifically arachidonic acid and docosahexaenoic acid (DHA), accrue rapidly in the grey matter of the brain during development, and brain fatty acid (FA) composition reflects dietary availability. Membrane lipid components can influence signal transduction cascades in various ways, which in the case of LCPUFA include the important regulatory functions mediated by the eicosanoids, and extend to long-term regulation through effects on gene transcription. Our work indicates that FA imbalance as well as specific FA deficiencies can affect development adversely, including the ability to respond to environmental stimulation. For example, although the impaired water-maze performance of mice fed a saturated-fat diet improved in response to early environmental enrichment, the brains of these animals showed less complex patterns of dendritic branching. Dietary n-3 FA deficiency influences specific neurotransmitter systems, particularly the dopamine systems of the frontal cortex. We showed that dietary deficiency of n-3 FA impaired the performance of rats on delayed matching-to-place in the water maze, a task of the type associated with prefrontal dopamine function. We did not, however, find an association over a wider range of brain DHA levels and performance on this task. Some, but not all, studies of human infants suggest that dietary DHA may play a role in cognitive development as well as in some neurodevelopmental disorders; this possibility has important implications for population health.

Nitric oxide as the mediator of the antiosteoporotic actions of estrogen, statins, and essential fatty acids

Estrogen, statins, and essential fatty acids and their metabolites can prevent osteoporosis. However, it is not certain how these three structurally different agents can have the same beneficial action. It is suggested that all three, in addition to their other modes of action in the prevention of osteoporosis, have the ability to augment constitutional (or endothelial) nitric oxide generation, which is known to be beneficial in osteoporosis. If so, it will be interesting to study whether nitric oxide donors and/or nitric oxide precursors can be given together with estrogen, statins, or essential fatty acids to potentiate their benefit in osteoporosis.

Nutritional factors in the pathobiology of human essential hypertension

Endothelial cells produce vasodilator and vasoconstrictor substances. Dietary factors such as sodium, potassium, calcium, magnesium, zinc, selenium, vitamins A, C, and E, and essential fatty acids and their products such as eicosanoids can influence blood pressure, cardio- and cerebrovascular diseases, and concentrations of blood lipids and atherosclerosis. There might be a close interaction between these dietary factors, sympathetic and parasympathetic nervous systems, the metabolism of essential fatty acids, nitric oxide, prostacyclin, and endothelium in human essential hypertension. A deficiency in any one factor, dietary or endogenous, or alterations in their interactions with each other, can lead to endothelial dysfunction and development of hypertension. Therefore, alterations in the metabolism of essential fatty acids might be a predisposing factor to the development of essential hypertension and insulin resistance.

Essential fatty acids in visual and brain development

Essential fatty acids are structural components of all tissues and are indispensable for cell membrane synthesis; the brain, retina and other neural tissues are particularly rich in long-chain polyunsaturated fatty acids (LC-PUFA). These fatty acids serve as specific precursors for eicosanoids, which regulate numerous cell and organ functions. Recent human studies support the essential nature of n-3 fatty acids in addition to the well-established role of n-6 essential fatty acids in humans, particularly in early life. The main findings are that light sensitivity of retinal rod photoreceptors is significantly reduced in newborns with n-3 fatty acid deficiency, and that docosahexaenoic acid (DHA) significantly enhances visual acuity maturation and cognitive functions. DHA is a conditionally essential nutrient for adequate neurodevelopment in humans. Comprehensive clinical studies have shown that dietary supplementation with marine oil or single-cell oil sources of LC-PUFA results in increased blood levels of DHA and arachidonic acid, as well as an associated improvement in visual function in formula-fed infants matching that of human breast-fed infants. The effect is mediated not only by the known effects on membrane biophysical properties, neurotransmitter content, and the corresponding electrophysiological correlates but also by a modulating gene expression of the developing retina and brain. Intracellular fatty acids or their metabolites regulate transcriptional activation of gene expression during adipocyte differentiation and retinal and nervous system development. Regulation of gene expression by LC-PUFA occurs at the transcriptional level and may be mediated by nuclear transcription factors activated by fatty acids. These nuclear receptors are part of the family of steroid hormone receptors. DHA also has significant effects on photoreceptor membranes and neurotransmitters involved in the signal transduction process; rhodopsin activation, rod and cone development, neuronal dendritic connectivity, and functional maturation of the central nervous system.

The effects of treatment with alpha-lipoic acid or evening primrose oil on vascular hemostatic and lipid risk factors, blood flow, and peripheral nerve conduction in the streptozotocin-diabetic rat

Oxidative stress and defective fatty acid metabolism in diabetes may lead to impaired nerve perfusion and contribute to the development of peripheral neuropathy. We studied the effects of 2-week treatments with evening primrose oil (EPO; n = 16) or the antioxidant alpha-lipoic acid (ALA; n = 16) on endoneurial blood flow, nerve conduction parameters, lipids, coagulation, and endothelial factors, in rats with streptozotocin-induced diabetes. Compared with their nondiabetic littermates, untreated diabetic rats had impaired sciatic motor and saphenous sensory nerve-conduction velocity (NCV; P <.001), reduced endoneurial blood flow (P <.001), and increased serum triglycerides (P <.01), cholesterol (P < 0.01), plasma factor VII (P <.0001), and von Willebrand factor (vWF; P <.0001). Plasma fibrinogen and serum high-density lipoprotein concentrations were not significantly different. Treatment with either ALA or EPO effectively corrected the deficits in NCV and endoneurial blood flow. ALA was associated with marked and statistically significant decreases in fibrinogen, factor VII, vWF, and triglycerides (P <.01, paired t tests before v after treatment). In contrast, EPO was associated with significant (P <.05) increases in fibrinogen, factor VII, vWF, triglycerides, and cholesterol and a significant decrease in high-density lipoprotein. Changes in levels of coagulation factors and lipids, qualitatively similar to those found with EPO, were obtained with a diet containing sunflower oil (to control for calorific and lipid content) or with a normal diet alone. Blood glucose and hematocrit levels were not significantly altered by treatments. These data suggest that although both ALA and EPO improve blood flow and nerve function, their actions on vascular factors differ. The marked effects of ALA in lowering lipid and hemostatic risk factors for cardiovascular disease indicate potential antithrombotic and antiatherosclerotic actions that could be of benefit in human diabetes and merit further study.

Dietary gamma-linolenic acid suppresses aortic smooth muscle cell proliferation and modifies atherosclerotic lesions in apolipoprotein E knockout mice

The present study was conducted to evaluate the antiatherogenic effects of dietary gamma-linolenic acid (GLA) (primrose oil) in apolipoprotein E (apoE) genetic knockout mice. Five-wk-old male mice were fed cholesterol-free diets containing 10 g/100 g lipid as corn oil (CO) [control diet, 0 mol/100 mol GLA and (n-3) polyunsaturated fatty acids (PUFA)], primrose oil (PO, 10 mol/100 mol GLA), fish oil-CO mix [FC; 9:1 wt/wt, 0 mol/100 mol GLA and 17 mol/100 mol (n-3) PUFA] or fish oil-PO mix [FP, 1:3 wt/wt, 8 mol/100 mol GLA and 5 mol/100 mol (n-3) PUFA] for 15 wk. Subsequently, diets were supplemented with cholesterol (1.25 g/100 g) and sodium cholate (0.5 g/100 g) and fed for an additional 10 and 16 wk. Plasma cholesterol and triglyceride levels generally did not differ among groups at 20, 30 and 36 wk of age. Mice fed GLA-containing diets (PO and FP) had significantly (P < 0.05) higher liver phospholipid levels of dihomo-gamma-linolenic acid, the elongated product of GLA, relative to CO and FC groups. Consumption of GLA (PO and FP diets) significantly reduced (P < 0.05) aortic vessel wall medial layer thickness at 20 and 30 wk. A parallel GLA-dependent suppression in the number of proliferating (proliferating cell nuclear antigen positive) aortic smooth muscle cells was also observed. Diets containing either GLA or (n-3) PUFA reduced (P < 0.05) atherosclerotic lesion size in 30-wk-old mice. These results indicate that dietary GLA can suppress smooth muscle cell proliferation in vivo and retard the development of diet-induced atherosclerosis in apoE knockout mice.

Fatty acid regulates gene expression and growth of human prostate cancer PC-3 cells

It has been proposed that the omega-6 fatty acids increase the rate of tumor growth. Here we test that hypothesis in the PC-3 human prostate tumor. We found that the essential fatty acids, linoleic acid (LA) and arachidonic acid (AA), and the AA metabolite PGE(2) stimulate tumor growth while oleic acid (OA) and the omega-3 fatty acid, eicosapentaenoic acid (EPA) inhibited growth. In examining the role of AA in growth response, we extended our studies to analyze changes in early gene expression induced by AA. We demonstrate that c-fos expression is increased within minutes of addition in a dose-dependent manner. Moreover, the immediate early gene cox-2 is also increased in the presence of AA in a dose-dependent manner, while the constitutive cox-1 message was not increased. Three hours after exposure to AA, the synthesis of PGE(2) via COX-2 was also increased. Previous studies have demonstrated that AA was primarily delivered by low density lipoprotein (LDL) via its receptor (LDLr). Since it is known that hepatomas, acute myelogenous leukemia and colorectal tumors lack normal cholesterol feedback, we examined the role of the LDLr in growth regulation of the PC-3 prostate cancer cells. Analysis of ldlr mRNA expression and LDLr function demonstrated that human PC-3 prostate cancer cells lack normal feedback regulation. While exogenous LDL caused a significant stimulation of cell growth and PGE(2) synthesis, no change was seen in regulation of the LDLr by LDL. Taken together, these data show that normal cholesterol feedback of ldlr message and protein is lost in prostate cancer. These data suggest that unregulated over-expression of LDLr in tumor cells would permit increased availability of AA, which induces immediate early genes c-fos and cox-2 within minutes of uptake.

Dietary trans fatty acids combined with a marginal essential fatty acid status during the pre- and postnatal periods do not affect growth or brain fatty acids but may alter behavioral development in B6D2F(2) mice

The objective of this study was to investigate whether dietary trans fatty acids (TFA) during the pre- and postnatal periods would exacerbate the effects of marginal essential fatty acid (EFA) status on growth, brain long-chain polyunsaturated fatty acids (LC-PUFA) and behavioral development in B6D2F(2) mice. Pregnant B6D2F(1) females were randomly assigned to one of the following three diets: marginal EFA plus 22% trans 18:1 (mEFA + TFA); marginal EFA (mEFA); and control (CON). The total 18:1 content in all diets was similar. The offspring were weaned and maintained on the same diets. Both the mEFA and mEFA + TFA groups had reduced growth and brain weight compared with CON, but did not differ from one another. As expected, the mEFA and mEFA + TFA groups had reduced docosahexaenoic acid [DHA; 22:6(n-3)]) and increased 22:5(n-6) concentrations in brain phosphatidylcholine (PC) and phosphatidylethanolamine (PE) compared with the CON group, but again did not differ from one another. Reversal learning in the T-water maze was significantly slower in the mEFA + TFA groups compared with the mEFA group and both were slower than the CON group. These findings illustrate that TFA combined with a marginal EFA status do not exacerbate the effects of marginal EFA status on growth or brain LC-PUFA. However, long-term effects of dietary TFA during the pre- and postnatal period on behavioral development and neural function should be investigated in future studies.

Modulation of intestinal vitamin D receptor availability and calcium ATPase activity by essential fatty acids

The physiological mechanisms by which essential fatty acids (EFAs) affect calcium (Ca(2+)) retention is not clear, but suggestions have included changes in membrane fluidity, receptor modulation and induction of second messengers. The vitamin D receptor (VDR) is essential for the functioning of 1,25(OH)(2)D(3)which increases Ca(2+)absorption. Activity of the intestinal basolateral membrane (BLM) Ca(2+)ATPase correlates with the degree of Ca(2+)absorption. Therefore, changes in ATPase activity and VDR availability due to EFAs may influence calcium retention. We have investigated the effect of long-term dietary supplementation with EFAs on Ca(2+)ATPase activity (measured colourimetrically) and VDR availability (measured with the ELISA technique) after the loss of oestrogen induced by ovariectomy (OVX) in female Sprague Dawley rats. Control animals underwent anaesthesia and a surgical procedure but the ovaries were left intact (sham). Ca(2+)ATPase activity was significantly lower in OVX animals than in the intact animals (P<0.05) and following supplementation with EFAs, was significantly higher than in sham controls (P<0.05). A higher number of VDR was measured after OVX and declined due to EFA supplementation; these differences in activity of the ATPase and number of receptors could be ascribed to membrane changes due to EFA supplementation, feedback control by serum calcium or the direct influence of the EFAs.

Can manipulation of the ratios of essential fatty acids slow the rapid rate of postmenopausal bone loss?

The rapid rate of postmenopausal bone loss is mediated by the inflammatory cytokines interleukin-1, interleukin-6, and tumor necrosis factor alpha. Dietary supplementation with fish oil, flaxseeds, and flaxseed oil in animals and healthy humans significantly reduces cytokine production while concomitantly increasing calcium absorption, bone calcium, and bone density. Possibilities may exist for the therapeutic use of the omega-3 fatty acids, as supplements or in the diet, to blunt the increase of the inflammatory bone resorbing cytokines produced in the early postmenopausal years, in order to slow the rapid rate of postmenopausal bone loss. Evidence also points to the possible benefit of gamma-linolenic acid in preserving bone density.

Lack of effect of supplementation with essential fatty acids on bone mineral density in healthy pre- and postmenopausal women: two randomized controlled trials of Efacal v. calcium alone

Randomized controlled trials of the effects of the dietary supplement Efacal (Scotia Pharmaceuticals Plc, Guildford, Surrey, UK) v. Ca only on total body bone mineral density (BMD) and markers of bone turnover were conducted in healthy pre- and postmenopausal women separately. Total daily dose for 12 months for the Efacal groups was: Ca 1.0 g, evening primrose oil 4.0 g and marine fish oil 440 mg; and for the control groups was: Ca 1.0 g. Reported compliance was better than 90% in both age groups. For the forty-three premenopausal women (age range 25-40 years), initial mean total body BMD values were similar for Efacal and control groups and both groups showed highly significant mean increases of about 1%; however, there were no significant between-group differences for the changes in BMD or markers of bone turnover. For the forty-two postmenopausal women (age range 50-65 years), initial mean total body BMD values were again well-matched across treatment groups. Both Efacal and control groups showed highly significant decreases in total body BMD of about 1%, but again there were no significant between-group differences in total body BMD or markers of bone turnover. Possible confounding variables such as initial total body BMD were explored but had no effect on the outcome in either age group. Nail quality improved in both age groups and in both Efacal and control groups. Again, there was no significant difference between treatment groups. No evidence was found to support a beneficial effect of Efacal on BMD in these women.