Dietary resistant starch supplementation increases gut luminal deoxycholic acid abundance in mice.

Bile acids (BA) are among the most abundant metabolites produced by the gut microbiome. Primary BAs produced in the liver are converted by gut bacterial 7-α-dehydroxylation into secondary BAs, which can differentially regulate host health via signaling based on their varying affinity for BA receptors. Despite the importance of secondary BAs in host health, the regulation of 7-α-dehydroxylation and the role of diet in modulating this process is incompletely defined. Understanding this process could lead to dietary guidelines that beneficially shift BA metabolism. Dietary fiber regulates gut microbial composition and metabolite production. We tested the hypothesis that feeding mice a diet rich in a fermentable dietary fiber, resistant starch (RS), would alter gut bacterial BA metabolism. Male and female wild-type mice were fed a diet supplemented with RS or an isocaloric control diet (IC). Metabolic parameters were similar between groups. RS supplementation increased gut luminal deoxycholic acid (DCA) abundance. However, gut luminal cholic acid (CA) abundance, the substrate for 7-α-dehydroxylation in DCA production, was unaltered by RS. Further, RS supplementation did not change the mRNA expression of hepatic BA producing enzymes or ileal BA transporters. Metagenomic assessment of gut bacterial composition revealed no change in the relative abundance of bacteria known to perform 7-α-dehydroxylation. P. ginsenosidimutans and P. multiformis were positively correlated with gut luminal DCA abundance and increased in response to RS supplementation. These data demonstrate that RS supplementation enriches gut luminal DCA abundance without increasing the relative abundance of bacteria known to perform 7-α-dehydroxylation.

Feeding mice a diet high in oxidized linoleic acid metabolites does not alter liver oxylipin concentrations.

The oxidation of dietary linoleic acid (LA) produces oxidized LA metabolites (OXLAMs) known to regulate multiple signaling pathways in vivo. Recently, we reported that feeding OXLAMs to mice resulted in liver inflammation and apoptosis. However, it is not known whether this is due to a direct effect of OXLAMs accumulating in the liver, or to their degradation into bioactive shorter chain molecules (e.g. aldehydes) that can provoke inflammation and related cascades. To address this question, mice were fed a low or high LA diet low in OXLAMs, or a low LA diet supplemented with OXLAMs from heated corn oil (high OXLAM diet). Unesterified oxidized fatty acids (i.e. oxylipins), including OXLAMs, were measured in liver after 8 weeks of dietary intervention using ultra-high pressure liquid chromatography coupled to tandem mass-spectrometry. The high OXLAM diet did not alter liver oxylipin concentrations compared to the low LA diet low in OXLAMs. Significant increases in several omega-6 derived oxylipins and reductions in omega-3 derived oxylipins were observed in the high LA dietary group compared to the low LA group. Our findings suggest that dietary OXLAMs do not accumulate in liver, and likely exert pro-inflammatory and pro-apoptotic effects via downstream secondary metabolites.

Quantitation of Oxylipins in Fish and Algae Oil Supplements Using Optimized Hydrolysis Procedures and Ultra-High Performance Liquid Chromatography Coupled to Tandem Mass-Spectrometry.

Fish and algae oil supplements are enriched with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are precursors to oxidized fatty acids, known as oxylipins. Here, we optimized a base hydrolysis method for measuring oxylipins in oil with ultrahigh-performance liquid chromatography coupled to tandem mass-spectrometry (UPLC-MS/MS) and quantified them in fish and algae oil supplements. Hydrolysis of 2 µL of oil with sodium carbonate resulted in greater oxylipin concentrations and minimal matrix effects, compared to higher oil volumes (10, 20, and 30 µL). Oxylipin yield was higher when oil was hydrolyzed in methanol containing 0.1% acetic acid and 0.1% butylated hydroxytoluene, compared to no methanol, and using sodium hydroxide versus sodium carbonate. Oxylipins extracted from 2 µL of oil using sodium hydroxide in solvent showed that EPA-derived oxylipins were most abundant in fish oil (84-87%), whereas DHA-oxylipins were abundant in algae oil (83%). This study shows that fish and algae oils are direct sources of EPA- and DHA-derived oxylipins.

Plasma oxylipins and unesterified precursor fatty acids are altered by DHA supplementation in pregnancy: Can they help predict risk of preterm birth?

Oxidized lipids derived from omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids, collectively known as oxylipins, are bioactive signaling molecules that play diverse roles in human health and disease. Supplementation with n-3 docosahexaenoic acid (DHA) during pregnancy has been reported to decrease the risk of preterm birth in singleton pregnancies, which may be due to effects of DHA supplementation on oxylipins or their precursor n-6 and n-3 fatty acids. There is only limited understanding of the levels and trajectory of changes in plasma oxylipins during pregnancy, effects of DHA supplementation on oxylipins and unesterified fatty acids, and whether and how oxylipins and their unesterified precursor fatty acids influence preterm birth. In the present study we used liquid chromatography-tandem mass spectrometry to profile oxylipins and their precursor fatty acids in the unesterified pool using plasma samples collected from a subset of pregnant Australian women who participated in the ORIP (Omega-3 fats to Reduce the Incidence of Prematurity) study. ORIP is a large randomized controlled trial testing whether daily supplementation with n-3 DHA can reduce the incidence of early preterm birth compared to control. Plasma was collected at study entry (≈pregnancy week 14) and again at ≈week 24, in a subgroup of 48 ORIP participants-12 cases with spontaneous preterm (<37 weeks) birth and 36 matched controls with spontaneous term (≥40 weeks) birth. In the combined preterm and term pregnancies, we observed that in the control group without DHA supplementation unesterified AA and AA-derived oxylipins 12-HETE, 15-HETE and TXB2 declined between weeks 14-24 of pregnancy. Compared to control, DHA supplementation increased unesterified DHA, EPA, and AA, DHA-derived 4-HDHA, 10-HDHA and 19,20-EpDPA, and AA-derived 12-HETE at 24 weeks. In exploratory analysis independent of DHA supplementation, participants with concentrations above the median for 5-lipoxygenase derivatives of AA (5-HETE, Odds Ratio (OR) 8.2; p = 0.014) or DHA (4-HDHA, OR 8.0; p = 0.015) at 14 weeks, or unesterified AA (OR 5.1; p = 0.038) at 24 weeks had higher risk of spontaneous preterm birth. The hypothesis that 5-lipoxygenase-derived oxylipins and unesterified AA could serve as mechanism-based biomarkers predicting spontaneous preterm birth should be evaluated in larger, adequately powered studies.

Linoleic acid-good or bad for the brain?

Increased intake of omega-6 rich plant oils such as soybean and corn oil over the past few decades has inadvertently tripled the amount of n-6 linoleic acid (LA, 18:2n-6) in the diet. Although LA is nutritionally "essential", very little is known about how it affects the brain when present in excess. This review provides an overview on the metabolism of LA by the brain and the effects of excess dietary LA intake on brain function. Pre-clinical evidence suggests that excess dietary LA increases the brain's vulnerability to inflammation and likely acts via its oxidized metabolites. In humans, excess maternal LA intake has been linked to a typical neurodevelopment, but underlying mechanisms are unknown. It is concluded that excess dietary LA may adversely affect the brain. The potential neuroprotective role of reducing dietary LA merits clinical evaluation in future studies.

Intravenous fat induces changes in PUFA and their bioactive metabolites: Comparison between Japanese and Australian preterm infants.

OBJECTIVE: Oxylipins are biologically active signaling molecules that initiate and resolve inflammation; they are synthesized by oxidation of polyunsaturated fatty acids (PUFAs) and reflect PUFA intake and status. The PUFA intake in preterm infants differs between countries because of the type of lipid emulsions used and the PUFA content of breast milk. We compared total blood PUFA, free PUFA and their oxylipin levels in dried whole blood samples from preterm infants born in Australia and Japan. METHODS: We enrolled 30 and 14 preterm infants born less than 31 weeks' gestation, from Adelaide and Japan respectively. Blood samples were obtained from cord blood, and on postnatal days 4, 7, 14 and 28. Total PUFAs were measured using gas chromatography, while free fatty acids and oxylipins were screened using ultra high-performance liquid chromatography mass spectroscopy. RESULTS: Differences in the levels of blood PUFA between the centres were found which were in line with the timing and type of lipid emulsion administration. Significant differences in longitudinal levels were seen more often in free PUFA and their oxylipins than in total blood PUFA. This was particularly true for AA and DHA. In contrast, differences in the levels could be seen in total blood EPA, as well as in free EPA and its oxylipins. Further, levels of many free PUFA and their oxylipins were higher in Japanese infants than in Australian infants. CONCLUSION: Differences in total and free fatty acids and unesterified oxylipins, were observed during the first weeks of life and between preterm infants born in Australia and Japan, which were likely a reflection of the type of lipid emulsion and timing of administration. The clinical significance of these changes remains to be explored.

Altered soluble epoxide hydrolase-derived oxylipins in patients with seasonal major depression: An exploratory study.

Many cytochrome p450-derived lipids promote resolution of inflammation, in contrast to their soluble epoxide hydrolase(sEH)-derived oxylipin breakdown products. Here we compare plasma oxylipins and precursor fatty acids between seasons in participants with major depressive disorder with seasonal pattern (MDD-s). Euthymic participants with a history of MDD-s recruited in summer-fall were followed-up in winter. At both visits, a structured clinical interview (DSM-5 criteria) and the Beck Depression Inventory II (BDI-II) were administered. Unesterified and total oxylipin pools were assayed by liquid chromatography tandem mass-spectrometry (LC-MS/MS). Precursor fatty acids were measured by gas chromatography. In nine unmedicated participants euthymic at baseline who met depression criteria in winter, BDI-II scores increased from 4.9±4.4 to 19.9±7.7. Four sEH-derived oxylipins increased in winter compared to summer-fall with moderate to large effect sizes. An auto-oxidation product (unesterified epoxyketooctadecadienoic acid) and lipoxygenase-derived 13-hydroxyoctadecadienoic acid also increased in winter. The cytochrome p450-derived 20-COOH-leukotriene B4 (unesterified) and total 14(15)-epoxyeicosatetraenoic acid, and the sEH-derived 14,15-dihydroxyeicostrienoic acid (unesterified), decreased in winter. We conclude that winter depression was associated with changes in cytochrome p450- and sEH-derived oxylipins, suggesting that seasonal shifts in omega-6 and omega-3 fatty acid metabolism mediated by sEH may underlie inflammatory states in symptomatic MDD-s.

Lipidomic Analysis of Oxidized Fatty Acids in Plant and Algae Oils.

Linoleic acid (LA) and α-linolenic acid (ALA) in plant or algae oils are precursors to oxidized fatty acid metabolites known as oxylipins. Liquid chromatography tandem mass spectrometry was used to quantify oxylipins in soybean, corn, olive, canola, and four high-oleic acid algae oils at room temperature or after heating for 10 min at 100 °C. Flaxseed oil oxylipin concentrations were determined in a follow-up experiment that compared it to soybean, canola, corn, and olive oil. Published consumption data for soybean, canola, corn, and olive oil were used to estimate daily oxylipin intake. The LA and ALA fatty acid composition of the oils was generally related to their respective oxylipin metabolites, except for olive and flaxseed oil, which had higher LA derived monohydroxy and ketone oxylipins than other oils, despite their low LA content. Algae oils had the least amount of oxylipins. The change in oxylipin concentrations was not significantly different among the oils after short-term heating. The estimated oxylipin intake from nonheated soybean, canola, corn, and olive oil was 1.1 mg per person per day. These findings suggest that oils represent a dietary source of LA and ALA derived oxylipins and that the response of oils to short-term heating does not differ among the various oils.

Omega-3 fatty acids (ῳ-3 fatty acids) in epilepsy: animal models and human clinical trials.

INTRODUCTION: There is growing interest in alternative and nutritional therapies for drug resistant epilepsy. ῳ-3 fatty acids such as fish or krill oil are widely available supplements used to lower triglycerides and enhance cardiovascular health. ῳ-3 fatty acids have been studied extensively in animal models of epilepsy. Yet, evidence from randomized controlled clinical trials in epilepsy is at an early stage. AREAS COVERED: This report focuses on the key ῳ-3 fatty acids DHA and EPA, their incorporation into the lipid bilayer, modulation of ion channels, and mechanisms of action in reducing excitability within the central nervous system. This paper presents pre-clinical evidence from mouse, rat, and canine models, and reports the efficacy of n-3 fatty acids in randomized controlled clinical trials. An English language search of PubMed and Google scholar for the years 1981-2016 was performed for animal studies and human randomized controlled clinical trials. Expert commentary: Basic science and animal models provide a cogent rationale and substantial evidence for a role of ῳ-3 fatty acids in reducing seizures. Results in humans are limited. Recent Phase II RCT evidence suggests that low to moderate dose of ῳ-3 fatty acids reduce seizures; however, larger multicenter randomized trials are needed to confirm or refute the evidence. The safety, health effects, low cost and ease of use make ῳ-3 fatty acids an intriguing alternative therapy for drug resistant epilepsy. Though safety of profile is excellent, the human data is not yet sufficient to support efficacy in drug resistant epilepsy at this time.

Dietary linoleic acid-induced alterations in pro- and anti-nociceptive lipid autacoids: Implications for idiopathic pain syndromes?

BACKGROUND: Chronic idiopathic pain syndromes are major causes of personal suffering, disability, and societal expense. Dietary n-6 linoleic acid has increased markedly in modern industrialized populations over the past century. These high amounts of linoleic acid could hypothetically predispose to physical pain by increasing the production of pro-nociceptive linoleic acid-derived lipid autacoids and by interfering with the production of anti-nociceptive lipid autacoids derived from n-3 fatty acids. Here, we used a rat model to determine the effect of increasing dietary linoleic acid as a controlled variable for 15 weeks on nociceptive lipid autacoids and their precursor n-6 and n-3 fatty acids in tissues associated with idiopathic pain syndromes. RESULTS: Increasing dietary linoleic acid markedly increased the abundance of linoleic acid and its pro-nociceptive derivatives and reduced the abundance of n-3 eicosapentaenoic acid and docosahexaenoic acid and their anti-nociceptive monoepoxide derivatives. Diet-induced changes occurred in a tissue-specific manner, with marked alterations of nociceptive lipid autacoids in both peripheral and central tissues, and the most pronounced changes in their fatty acid precursors in peripheral tissues. CONCLUSIONS: The present findings provide biochemical support for the hypothesis that the high linoleic acid content of modern industrialized diets may create a biochemical susceptibility to develop chronic pain. Dietary linoleic acid lowering should be further investigated as part of an integrative strategy for the prevention and management of idiopathic pain syndromes.

Threshold changes in rat brain docosahexaenoic acid incorporation and concentration following graded reductions in dietary alpha-linolenic acid.

BACKGROUND: This study tested the dietary level of alpha-linolenic acid (α-LNA, 18:3n-3) required to maintain brain (14)C-Docosahexaenoic acid (DHA, 22:6n-3) metabolism and concentration following graded α-LNA reduction. METHODS: Fischer-344 (CDF) male rat pups (18-21 days old) were randomized to the AIN-93G diet containing as a % of total fatty acids, 4.6% ("n-3 adequate"), 3.6%, 2.7%, 0.9% or 0.2% ("n-3 deficient") α-LNA for 15 weeks. Rats were intravenously infused with (14)C-DHA to steady state for 5 min, serial blood samples collected to obtain plasma, and brains excised following microwave fixation. Labeled and unlabeled DHA concentrations were measured in plasma and brain to calculate the incorporation coefficient, k*, and incorporation rate, J(in). RESULTS: Compared to 4.6% α-LNA controls, k* was significantly increased in ethanolamine glycerophospholipids in the 0.2% α-LNA group. Circulating unesterified DHA and brain incorporation rates (J(in)) were significantly reduced at 0.2% α-LNA. Brain total lipid and phospholipid DHA concentrations were reduced at or below 0.9% α-LNA. CONCLUSION: Threshold changes for brain DHA metabolism and concentration were maintained at or below 0.9% dietary α-LNA, suggesting the presence of homeostatic mechanisms to maintain brain DHA metabolism when dietary α-LNA intake is low.

Targeted alterations in dietary n-3 and n-6 fatty acids improve life functioning and reduce psychological distress among patients with chronic headache: a secondary analysis of a randomized trial.

Omega-3 and omega-6 fatty acids are precursors of bioactive lipid mediators posited to modulate both physical pain and psychological distress. In a randomized trial of 67 subjects with severe headaches, we recently demonstrated that targeted dietary manipulation-increasing omega-3 fatty acids with concurrent reduction in omega-6 linoleic acid (the H3-L6 intervention)-produced major reductions in headache compared with an omega-6 lowering (L6) intervention. Because chronic pain is often accompanied by psychological distress and impaired health-related quality of life (HRQOL), we used data from this trial to examine whether the H3-L6 intervention favorably impacted these domains. Additionally, we examined the effect of the interventions on the number of cases with substantial physical or mental impairments as defined by cutoff values in the Brief Symptom Inventory (BSI-18), Medical Outcomes Study Short Forms 12 (SF-12), Headache Impact Test (HIT-6), and the number of headache days per month. In the intention-to-treat analysis, participants in the H3-L6 group experienced statistically significant reductions in psychological distress (BSI-18 mean difference: -6.56; 95% confidence interval [CI]: -11.43 to -1.69) and improvements in SF-12 mental (mean difference: 6.01; 95% CI: 0.57 to 11.45) and physical (mean difference: 6.65; 95% CI: 2.14 to 11.16) health summary scores. At 12 weeks, the proportion of subjects experiencing substantial impairment according to cutoff values in the BSI-18, SF-12 physical, HIT-6, and headache days per month was significantly lower in the H3-L6 group. Dietary manipulation of n-3 and n-6 fatty acids, previously shown to produce major improvements in headache, was found to also reduce psychological distress and improve HRQOL and function.

Neuropathological responses to chronic NMDA in rats are worsened by dietary n-3 PUFA deprivation but are not ameliorated by fish oil supplementation.

BACKGROUND: Dietary long-chain n-3 polyunsaturated fatty acid (PUFA) supplementation may be beneficial for chronic brain illnesses, but the issue is not agreed on. We examined effects of dietary n-3 PUFA deprivation or supplementation, compared with an n-3 PUFA adequate diet (containing alpha-linolenic acid [18:3 n-3] but not docosahexaenoic acid [DHA, 22:6n-3]), on brain markers of lipid metabolism and excitotoxicity, in rats treated chronically with NMDA or saline. METHODS: Male rats after weaning were maintained on one of three diets for 15 weeks. After 12 weeks, each diet group was injected i.p. daily with saline (1 ml/kg) or a subconvulsive dose of NMDA (25 mg/kg) for 3 additional weeks. Then, brain fatty acid concentrations and various markers of excitotoxicity and fatty acid metabolism were measured. RESULTS: Compared to the diet-adequate group, brain DHA concentration was reduced, while n-6 docosapentaenoic acid (DPA, 22:5n-6) concentration was increased in the n-3 deficient group; arachidonic acid (AA, 20:4n-6) concentration was unchanged. These concentrations were unaffected by fish oil supplementation. Chronic NMDA increased brain cPLA2 activity in each of the three groups, but n-3 PUFA deprivation or fish oil did not change cPLA2 activity or protein compared with the adequate group. sPLA2 expression was unchanged in the three conditions, whereas iPLA2 expression was reduced by deprivation but not changed by supplementation. BDNF protein was reduced by NMDA in N-3 PUFA deficient rats, but protein levels of IL-1ß, NGF, and GFAP did not differ between groups. CONCLUSIONS: N-3 PUFA deprivation significantly worsened several pathological NMDA-induced changes produced in diet adequate rats, whereas n-3 PUFA supplementation did not affect NMDA induced changes. Supplementation may not be critical for this measured neuropathology once the diet has an adequate n-3 PUFA content.

Dietary omega-6 fatty acid lowering increases bioavailability of omega-3 polyunsaturated fatty acids in human plasma lipid pools.

BACKGROUND: Dietary linoleic acid (LA, 18:2n-6) lowering in rats reduces n-6 polyunsaturated fatty acid (PUFA) plasma concentrations and increases n-3 PUFA (eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) concentrations. OBJECTIVE: To evaluate the extent to which 12 weeks of dietary n-6 PUFA lowering, with or without increased dietary n-3 PUFAs, alters unesterified and esterified plasma n-6 and n-3 PUFA concentrations in subjects with chronic headache. DESIGN: Secondary analysis of a randomized trial. Subjects with chronic headache were randomized for 12 weeks to (1) average n-3, low n-6 (L6) diet; or (2) high n-3, low n-6 LA (H3-L6) diet. Esterified and unesterified plasma fatty acids were quantified at baseline (0 weeks) and after 12 weeks on a diet. RESULTS: Compared to baseline, the L6 diet reduced esterified plasma LA and increased esterified n-3 PUFA concentrations (nmol/ml), but did not significantly change plasma arachidonic acid (AA, 20:4n-6) concentration. In addition, unesterified EPA concentration was increased significantly among unesterified fatty acids. The H3-L6 diet decreased esterified LA and AA concentrations, and produced more marked increases in esterified and unesterified n-3 PUFA concentrations. CONCLUSION: Dietary n-6 PUFA lowering for 12 weeks significantly reduces LA and increases n-3 PUFA concentrations in plasma, without altering plasma AA concentration. A concurrent increase in dietary n-3 PUFAs for 12 weeks further increases n-3 PUFA plasma concentrations and reduces AA.

A minimum of 3 months of dietary fish oil supplementation is required to raise amygdaloid afterdischarge seizure thresholds in rats--implications for treating complex partial seizures.

Complex partial seizures, which typically originate in limbic structures such as the amygdala, are often resistant to antiseizure medications. Our goal was to investigate the effects of chronic dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs) derived from fish oil on seizure thresholds in the amygdala, as well as on blood and brain PUFA levels. The acute effects of injected n-3 PUFAs--eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)--were also tested in the maximal pentylenetetrazol (PTZ) seizure model. In amygdala-implanted subjects, fish oil supplementation significantly increased amygdaloid afterdischarge thresholds, as compared with controls at 3, 5, and 7 months after the start of supplementation. Fish oil supplementation also increased serum EPA and DHA concentrations. DHA concentration in the pyriform-amygdala area increased in the fish-oil treated group by 17-34%, but this effect did not reach statistical significance (P=0.065). DHA significantly increased the latency to seizure onset in the PTZ seizure model, whereas EPA had no significant effect. These observations suggest that chronic dietary fish oil supplementation can raise focal amygdaloid seizure thresholds and that this effect is likely mediated by DHA rather than by EPA.

Upregulated expression of brain enzymatic markers of arachidonic and docosahexaenoic acid metabolism in a rat model of the metabolic syndrome.

BACKGROUND: In animal models, the metabolic syndrome elicits a cerebral response characterized by altered phospholipid and unesterified fatty acid concentrations and increases in pro-apoptotic inflammatory mediators that may cause synaptic loss and cognitive impairment. We hypothesized that these changes are associated with phospholipase (PLA2) enzymes that regulate arachidonic (AA, 20:4n-6) and docosahexaenoic (DHA, 22:6n-6) acid metabolism, major polyunsaturated fatty acids in brain. Male Wistar rats were fed a control or high-sucrose diet for 8 weeks. Brains were assayed for markers of AA metabolism (calcium-dependent cytosolic cPLA2 IVA and cyclooxygenases), DHA metabolism (calcium-independent iPLA2 VIA and lipoxygenases), brain-derived neurotrophic factor (BDNF), and synaptic integrity (drebrin and synaptophysin). Lipid concentrations were measured in brains subjected to high-energy microwave fixation. RESULTS: The high-sucrose compared with control diet induced insulin resistance, and increased phosphorylated-cPLA2 protein, cPLA2 and iPLA2 activity and 12-lipoxygenase mRNA, but decreased BDNF mRNA and protein, and drebrin mRNA. The concentration of several n-6 fatty acids in ethanolamine glycerophospholipids and lysophosphatidylcholine was increased, as was unesterified AA concentration. Eicosanoid concentrations (prostaglandin E2, thromboxane B2 and leukotriene B4) did not change. CONCLUSION: These findings show upregulated brain AA and DHA metabolism and reduced BDNF and drebrin, but no changes in eicosanoids, in an animal model of the metabolic syndrome. These changes might contribute to altered synaptic plasticity and cognitive impairment in rats and humans with the metabolic syndrome.

Gabapentin's minimal action on markers of rat brain arachidonic acid metabolism agrees with its inefficacy against bipolar disorder.

In rats, FDA-approved mood stabilizers used for treating bipolar disorder (BD) selectively downregulate brain markers of the arachidonic acid (AA) cascade, which are upregulated in postmortem BD brain. Phase III clinical trials show that the anticonvulsant gabapentin (GBP) is ineffective in treating BD. We hypothesized that GBP would not alter the rat brain AA cascade. Chronic GBP (10 mg/kg body weight, injected i.p. for 30 days) compared to saline vehicle did not significantly alter brain expression or activity of AA-selective cytosolic phospholipase A(2) (cPLA(2)) IVA or secretory (s)PLA(2) IIA, activity of cyclooxygenase-2, or prostaglandin E(2) or thromboxane B(2) concentrations. Plasma esterified and unesterified AA concentration was unaffected. These results, taken with evidence of an upregulated AA cascade in the BD brain and that approved mood stabilizers downregulate the rat brain AA cascade, support the hypothesis that effective anti-BD drugs act by targeting the brain AA cascade whereas ineffective drugs (such as GBP) do not target this pathway, and suggest that the rat model might be used for screening new anti-BD drugs.

The application of ultrasound energy to increase lipid extraction throughput of solid matrix samples (flaxseed).

Ultrasound may reduce lipid extraction times and increase analysis throughput of food materials. Ground flaxseed (25mg aliquots) were extracted in quadruplicate in 2:1 (v:v) chloroform:methanol, 3:2 hexane:isopropanol, 1:1 diethyl:petroleum ether or hexane with exposure to sonication at low frequencies of 20kHz with a 600W ultrasonic processor. Power was automatically varied to maintain constant amplitudes of 20%, 60% and 100% of 240microm for sonication exposures for 5, 10 and 20min, respectively. Total lipid dry weights and quantitative and qualitative fatty acids were determined. Results were compared to a standard 24-h, Folch-based, 2:1 chloroform:methanol extraction. Longer time exposures and higher sonication amplitudes were associated with increases in lipid recoveries. In particular, ultrasound-assisted extraction in 3:2 hexane:isopropanol for only 10min resulted in lipid and fatty acid recoveries similar to the 24-h standard method. Comprehensive testing on a variety of sample matrices and food products is required, but lipid extraction by ultrasound has potential to reduce sample processing time.

Dietary enrichment with medium chain triglycerides (AC-1203) elevates polyunsaturated fatty acids in the parietal cortex of aged dogs: implications for treating age-related cognitive decline.

Dogs demonstrate an age-related cognitive decline, which may be related to a decrease in the concentration of omega-3 polyunsaturated fatty acids (n-3 PUFA) in the brain. Medium chain triglycerides (MCT) increase fatty acid oxidation, and it has been suggested that this may raise brain n-3 PUFA levels by increasing mobilization of n-3 PUFA from adipose tissue to the brain. The goal of the present study was to determine whether dietary MCT would raise n-3 PUFA concentrations in the brains of aged dogs. Eight Beagle dogs were randomized to a control diet (n = 4) or an MCT (AC-1203) enriched diet (n = 4) for 2 months. The animals were then euthanized and the parietal cortex was removed for phospholipid, cholesterol and fatty acid determinations by gas-chromatography. Dietary enrichment with MCT (AC-1203) resulted in a significant increase in brain phospholipid and total lipid concentrations (P < 0.05). In particular, n-3 PUFA within the phospholipid, unesterified fatty acid, and total lipid fractions were elevated in AC-1203 treated subjects as compared to controls (P < 0.05). Brain cholesterol concentrations did not differ significantly between the groups (P > 0.05). These results indicate that dietary enrichment with MCT, raises n-3 PUFA concentrations in the parietal cortex of aged dogs.