Plasma Levels Of Linoleic Acid Research Articles

The changes in metabolomics profile induced by intermittent theta burst stimulation in major depressive disorder: an exploratory study

BackgroundRecently, there has been an ongoing interest in the mechanism of intermittent theta burst stimulation (iTBS) in major depressive disorder. Studying the metabolite changes induced by iTBS may help to understand the mechanism.MethodsEleven participants with major depressive disorder received 10 days iTBS treatment. Magnetic resonance imaging (MRI) was used to target the region of the left dorsolateral prefrontal cortex (DLPFC) in each participant. We analyzed the effects of iTBS on metabolites using high-throughput profiling and assessed its impact on depressive symptoms. These analyses were considered exploratory, and no correction for multiple comparisons was applied.ResultsAmong the 318 measured metabolites, a significant increase in cystine, asymmetric dimethylarginine (ADMA), 1-methylhistidine, indoleacetic acid (IAA), diethanolamine (DEA), dopa, riboflavin-5′-monophosphate (FMN), and a significant decrease in alphalinolenic acid (ALA), gamma-linolenic acid (GLA), serotonin, linoleic acid (LA) (p < 0.05) were detected in the patients after iTBS treatment. In Pearson correlation analysis, the plasma levels of LA, FMN and ADMA at baseline were significantly related to the reduction rate of the 17‐item Hamilton Depression Rating Scale and the Patient Health Questionnaire-9 scores (p < 0.05).ConclusionsOur study highlights that LA, FMN, ADMA and their relationship with oxidative stress, may be key factors in the antidepressant efficacy of iTBS.

Plasma n-6 Polyunsaturated Fatty Acid Levels and Survival in Renal Transplantation

The major n-6 polyunsaturated fatty acids linoleic acid (LA) and arachidonic acid (AA) play a role in inflammation and glucose metabolism, which could affect patient and renal transplant survival. In this single center cohort study of 1988 Norwegian renal transplant recipients, we assessed associations between plasma levels of LA and AA at baseline, measured by gas chromatography, and patient and graft survival, as well as inflammation and cardiovascular risk markers. During follow-up (median of 9.6years), 595 patients died and 805 renal transplants were lost, either due to recipient death or graft failure. In multivariable survival analysis, we found no associations with mortality for plasma levels of LA (hazard ratios: 0.99, 95% confidence intervals: 0.96-1.01) or AA (hazard ratios: 1.01, 95% confidence intervals: 0.96-1.06). No associations were found for cardiovascular mortality, overall graft loss, or death-censored graft loss. Plasma glucose, proglycemic marker chemerin, and proinflammatory marker growth differentiation factor 15 were inversely associated with plasma LA and positively associated with plasma AA levels in multivariable analysis. We found no associations between plasma levels of LA or AA and patient or graft survival. Plasma levels of LA and proglycemic indices were inversely associated, signaling a possible beneficial effect of LA consumption for prevention of posttransplantation diabetes mellitus.

Plasma linoleic acid partially mediates the association of bipolar disorder on self-reported mental health scales

We have shown that bipolar individuals have reduced quality diets, including lower intake of polyunsaturated fatty acids (PUFA). We have also reported reduced plasma levels of the n-6 PUFA, linoleic acid (LA), and the n-3 PUFA, eicosapentaenoic acid (EPA) in bipolar subjects. In the current analysis we hypothesized that LA and EPA plasma levels would mediate lower self-reported mental health and life functioning scores in bipolar subjects. In a cross-sectional study, we collected a 7-day diet record in bipolar (n = 56) and control subjects (n = 46) followed by a fasted blood draw. We used structured equation modeling path analysis to test for mediating effects of dietary intake and plasma levels of LA and EPA on self-reported mental health questionnaire scores, including the Life Functioning Questionnaire (LFQ), the Patient Health Questionnaire (PHQ9), and the Short Form Health Survey (SF12), extracting the mental health component summary score (SF12-MH). We adjusted for age, gender, psychiatric medication use, body mass index (BMI), and total caloric intake as covariates with bipolar disorder as the primary predictor. We found a significant path association from bipolar disorder to lower plasma LA levels (p = 0.03) and significant paths from plasma LA to PHQ9 (p = 0.05), LFQ (p = 0.01) and SF12-MH (p = 0.05) scores, such that lower plasma LA predicted worse outcomes. We found no significant paths from plasma EPA levels to any of the outcome measures. These findings suggest that plasma LA levels partially mediate the effect of bipolar disorder on self-reported measures of mental health and life functioning.

Abstract P233: Plasma essential fatty acids and type 2 diabetes risk: the Hoorn Study

Background: A high consumption of the polyunsaturated fatty acids linoleic acid (LA) and alpha-linolenic acid (ALA) instead of saturated fatty acids is known to reduce CHD risk, but data on the relation between LA and ALA intake and Type 2 Diabetes Mellitus (T2DM) risk are limited and inconsistent. Plasma levels of LA and ALA provide a relatively accurate reflection of the intake over several weeks or months, because of the essential nature of these fatty acids. Objective: To investigate the association of the percentage of LA and ALA in plasma lipids with fasting plasma glucose (FPG), post-load glucose (PLG) and glycated hemoglobin (HbA1c) as markers of T2DM risk. Methods: The study population included 667 Dutch men and women, aged 50-75 years from the population-based Hoorn Study. Baseline data for the current study were collected between 2000 and 2001, with follow-up in 2008. Linear regression models were used in cross-sectional and prospective analyses. Results: In cross-sectional analyses, plasma LA (per %) was significantly and inversely associated with FPG ( B = -0.022 [-0.044, 0.000]) and PLG ( B = -0.096 [-0.155, -0.036]), but not with HbA1c ( B = 0.000 [-0.014, 0.014]), after adjustment for age, gender, total energy intake, BMI, waist-to-hip ratio, physical activity, fiber, dietary saturated fat intake, alcohol intake and education level. In prospective analyses, plasma LA was not significantly associated with FPG, PLG or HbA1c after adjustments for baseline glucose. In addition, no significant associations were found between plasma ALA and markers of T2DM risk in cross-sectional or prospective analyses. Conclusion: Plasma LA, but not ALA, was inversely associated with fasting and post-load glucose levels in cross-sectional, but not in prospective analyses. Further studies are needed to elucidate the exact role of plasma LA and ALA levels and dietary polyunsaturated fatty acids in glucose metabolism.

Exposure to DEHP decreased four fatty acid levels in plasma of prepartum mice

Maternal exposure to di(2-ethylhexyl) phthalate (DEHP) decreased the plasma triglyceride in prepartum mice. To identify the fatty acid (FA) species involved and to understand the underlying mechanisms, pregnant Sv/129 wild-type (mPPARα), peroxisome proliferator-activated receptor α-null (Pparα-null) and humanized PPARα (hPPARα) mice were treated with diets containing 0%, 0.01%, 0.05% or 0.1% DEHP. Dams were dissected on gestational day 18 together with fetuses, and on postnatal day 2 together with newborns. n-3/n-6 polyunsaturated, saturated, and monounsaturated FAs in maternal plasma and in liver of wild-type offspring, and representative enzymes for FA desaturation and elongation in maternal liver, were measured. The plasma levels of linoleic acid, α-linolenic acid, palmitic acid and oleic acid were higher in the pregnant control mPPARa mice than in Ppara-null and hPPARa mice. DEHP exposure significantly decreased the levels of these four FAs only in pregnant mPPARα mice. Plasma levels of many FAs were higher in pregnant mice than in postpartum ones in a genotype-independent manner, while it was lower in the livers of fetuses than pups. DEHP exposure slightly increased hepatic arachidonic acid, α-linolenic acid, palmitoleic acid and oleic acid in fetuses, but not in pups. However, DEHP exposure did not clearly influence FA desaturase 1 and 2 nor elongase 2 and 5 expressions in the liver of all maternal mice. Taken together, the levels of plasma four FAs with shorter carbon chains were higher in pregnant mPPARα mice than in other genotypes, and DEHP exposure decreased these specific FA concentrations only in mPPARα mice, similarly to triglyceride levels.

Linoleic Acid, but not Oleic Acid, Upregulates Production of Interleukin-8 by Human Vascular Smooth Muscle Cells via Arachidonic Acid Metabolites Under Conditions of Oxidative Stress

Preeclampsia is associated with oxidative stress, elevated plasma levels of linoleic acid (LA), and increased vascular smooth muscle expression of the inflammatory chemokine, interleukin-8 (IL-8). We hypothesized that increased levels of LA under conditions of oxidative stress would increased production of IL-8 by vascular smooth muscle cells because LA is the dietary precursor to arachidonic acid (AA) and its metabolites that mediate inflammation. We also hypothesized that oleic acid (OA), which is not metabolized to AA metabolites, would not increase IL-8 under conditions of oxidative stress. To test this hypothesis, we cultured placental arterial smooth muscle (PASM) cells with an oxidizing solution enriched with LA (OxLA) or OA (OxOA). Media concentrations were analyzed for IL-8 and AA metabolites. Inhibitors were used to block the lipoxygenase and cyclooxygenase pathways. Exposure of cells to OxLA, but not to OxOA, significantly increased production of IL-8. OxLA also significantly increased production of AA metabolites. Nordihydroguaiaretic acid, an inhibitor of the lipoxygenase pathway, blocked IL-8 and leukotriene B4 (LTB4) production induced by OxLA, whereas indomethacin, an inhibitor of the cyclooxygenase pathway, blocked IL-8, prostaglandin E2 (PGE2), and thromboxane B2 (TXB2) production. Reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated gene expression in PASM cells for representative lipoxygenase (LTB4) and cyclooxygenase (thromboxane) metabolite receptors. PASM cells produced IL-8 in response to LA, but not OA, under conditions of oxidative stress. The IL-8 response was mediated by AA metabolites.

Neutrophils from pregnant women produce thromboxane and tumor necrosis factor-α in response to linoleic acid and oxidative stress

Preeclampsia is associated with oxidative stress, neutrophil activation, neutrophil infiltration into systemic vasculature, and elevated plasma levels of linoleic acid, the fatty acid precursor to arachidonic acid and its metabolite, thromboxane. In this study we evaluated whether linoleic acid under conditions of oxidative stress would stimulate neutrophil production of thromboxane and tumor necrosis factor-alpha. Neutrophils were isolated from 14 normal pregnant women. Western blot demonstrated cyclooxygenase-2 expression at 18 hours of incubation, so this incubation time was used for experiments. Neutrophils (2 x 10(6) cells/mL) were incubated in Dulbecco's modified Eagle's medium/F-12 with: (1) linoleic acid control; (2) an oxidizing solution enriched with linoleic acid; (3) oxidizing solution enriched with linoleic acid plus indomethacin; (4) oxidizing solution enriched with linoleic acid plus aspirin; (5) oxidizing solution enriched with linoleic acid plus NS-398, a specific inhibitor of cyclooxygenase-2; or (6) oxidizing solution enriched with linoleic acid plus pinane thromboxane, a thromboxane synthase inhibitor and receptor blocker. Oxidizing solution enriched with linoleic acid significantly increased oxidative stress in neutrophils. Compared with linoleic acid, oxidizing solution enriched with linoleic acid significantly increased neutrophil production of thromboxane and tumor necrosis factor-alpha. Indomethacin and aspirin inhibited oxidizing solution enriched with linoleic acid stimulation of thromboxane, but NS-398 was equally effective implicating cyclooxygenase-2 in the thromboxane response. Indomethacin inhibited oxidizing solution enriched with linoleic acid stimulation of tumor necrosis factor-alpha, but so did pinane thromboxane implicating thromboxane in the tumor necrosis factor-alpha response. These data demonstrate that exposure of neutrophils from normal pregnant women to conditions present in preeclamptic women results in neutrophil activation with release of thromboxane and tumor necrosis factor-alpha. Newly synthesized thromboxane is cyclooxygenase-2 dependent and plays a role in the tumor necrosis factor-alpha response. Our data suggest a mechanism for maternal vasoconstriction and vascular inflammation in preeclampsia because activated, thromboxane-secreting neutrophils migrate across endothelium into the microenvironment of the vasculature in which they could promote vasoconstriction, whereas release of tumor necrosis factor-alpha could cause vascular inflammation.

Plasma levels of polyunsaturated fatty acids in children with atopic dermatitis and in atopic and nonatopic controls

Atopic dermatitis has been thought to be associated with a disturbance in n-6 polyunsaturated fatty acid (PUFA) metabolism, but randomized trials investigating the clinical efficacy of oral supplementation with gammalinolenic acid have revealed conflicting results. To re-investigate the proposed linkage between PUFA dysregulation and atopic dermatitis. Plasma levels of linoleic acid (LA), gammalinolenic acid (GLA), dihomogammalinolenic acid (DGLA) and arachidonic acid (AA) were measured using HPLC in 22 children with atopic dermatitis. Patients were subdivided into those with elevated total serum IgE (group A, n = 15, IgE > +1 SD of age-specific normal values) and those with normal IgE (group B, n = 7) and compared with children suffering from allergic rhinitis/asthma (group C, n = 8) and with non-atopic controls (group D, n = 6). GLA levels were significantly lower (p < 0.05) in eczema patients with elevated IgE (A, 0.19 +/- 0.06%) and in atopic controls (C, 0.23 +/- 0.06%) than in eczema patients with low IgE (B, 0.42 +/- 0.19%) and non-atopic controls (D, 0.43 +/- 0.16%). There were no significant differences between groups for LIN, DGLA and AA, except for lower LIN levels in atopic controls. Correlation of individual LA and GLA values showed significantly steeper regression lines in low-IgE responders (B and D, k(x) = 0.058) than in high-IgE responders (A and C, k(x) = 0.012; p < 0.02), suggesting impaired delta-6-desaturase function in the latter. For the study population as a whole, there was a clear negative correlation between total levels of IgE and GLA (r(s) = -0.64) and a moderate negative correlation between total IgE and AA (r(s) = -0.38). Dysregulation of n-6 PUFA metabolism is neither consistently found in nor specifically associated with atopic dermatitis but rather appears to be associated with IgE production and atopy in general. The finding of decreased GLA levels in eczema patients with elevated total IgE and in children with allergic rhinitis and asthma but not in eczema patients with normal total IgE questions the proposed pathophysiologic role of fatty acid dysregulation in atopic dermatitis.

The effect of evening primrose oil on the radiation response and blood flow of mouse normal and tumour tissue

Purpose : To investigate the effect of the oral administration of evening primrose oil on the radiation response and the blood flow of normal tissue and a tumour in BALB/c mice. Methods and materials : Aliquots of evening primrose oil were fed to BALB/c mice daily and the radiation response of the skin was assessed by the determination of ED 50 values for the incidence of moist desquamation, using probit analysis. Tumour radiosensitivity was investigated by determining the growth delay caused by irradiation of a transplantable rhabdomyosarcoma. The 86 RbCl uptake technique was used to determine the blood flow in normal foot and tumour tissue. The fatty-acid content of red blood cells, plasma and tumour tissue was measured using gas chromatography. Results : Daily evening primrose oil dietary supplementation reduced the sensitivity of skin to radiation-induced moist desquamation and prevented the radiation-associated increase in blood flow that was observed in this tissue. No modification of tumour blood flow or of tumour sensitivity to radiation resulted from evening primrose oil supplementation of mice. Evening primrose oil supplementation resulted in changes in plasma levels of linoleic acid (LA), gamma-linolenic acid (GLA), dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (AA). These changes were contingent on whether the mice had been irradiated or not. In red blood cells evening primrose oil supplementation increased the GLA level of unirradiated mice and the LA level at 20 days after irradiation. There were no changes in tumour fatty-acid levels as a result of evening primrose oil treatment. Conclusions : Daily evening primrose oil supplementation reduced the sensitivity of skin to radiation-induced moist desquamation but did not alter tumour sensitivity to radiation.

Plasma fatty acids, prostaglandin F2alpha metabolite, and reproductive response in postpartum heifers fed rumen bypass fat.

An experiment was conducted to determine whether feeding rumen-protected fatty acids (FA) to postpartum heifers would increase plasma concentrations of linoleic acid and PGF2, metabolite (PGFM), shorten the interval from calving to first increase in plasma concentrations of progesterone (P4), and increase pregnancy rate relative to controls. Hereford x Angus heifers (346 kg) were assigned randomly to treatments containing either lipid or barley supplemented diets for the first 30 d postpartum. Lipid was .23 kg.heifer(-1).d(-1) of calcium salts of FA (CSFA; n = 20), and an isocaloric amount of barley served as the control (n = 19). Supplements, with .23 kg of barley as a vehicle, and a basal diet of meadow and alfalfa hays were pen fed to heifers (5/pen). Heifers were bled on alternate days (d1 to 30) and twice weekly (d 30 to 2 wk after first estrus) for RIA of plasma PGFM and P4, respectively. Weight percentage of major FA in plasma on d1 and 7 was determined with gas chromatography. First behavioral estrus was detected by use of intact bulls and confirmed by an increase in plasma P4. On d 7, but not d 1, plasma from heifers fed CSFA had altered proportions of major FA (P < .01), including an increase in linoleic acid compared with those of controls (29.1 vs 25.6% of total FA; SE = .75; P < .01). Analysis of variance of contrast variables revealed an effect of treatment on direction of change in PGFM from d 3 to 5 (P < .01). By d 7 and on d 9, plasma concentrations of PGFM were greater in heifers fed CSFA than in controls (P = .02 and P = .06, respectively). There was no difference in plasma concentration of PGFM between treatments on d 1, 3, 5, 11, 13, and 15 postpartum (P = .80, .17, .52, .82, .46, and .77, respectively). Days to first estrus with ovulation, pregnancy rate, and calving interval were not affected by treatments (P = .58, .52, and .24, respectively). Although supplemental lipid fed to primiparous beef heifers increased plasma levels of linoleic acid and production of PGFM in the early postpartum period, it did not improve the fertility of these heifers in the subsequent breeding season.

Changes in plasma and erythrocyte fatty acids in patients fed enteral formulas containing different fats.

Critically ill hospital patients were fed enteral formulas containing different fat substrates. Seven patients received formula X, which contained 28 g of structured triglycerides and menhaden oil to provide 7.6 g of medium-chain fatty acids, 2.5 g linoleic acid, 1.3 g eicosapentaenoic acid, and 0.4 g docosahexaenoic acid per 1000 mL of formula. Six patients received formula Y consisting of 36.8 g of medium-chain triglycerides and corn and soy oils providing 14.3 g medium-chain fatty acids and 11.7 g linoleic acid per 1000 mL. Feeding of formula X increased plasma total phospholipid levels of eicosapentaenoic acid on days 7 and 14 and docosahexaenoic acid levels on day 14. Plasma levels of linoleic acid were reduced in formula-X-fed in comparison to formula-Y-fed patients, whereas arachidonic acid was maintained in both groups during feeding. As a result of these changes, the patients receiving formula X had decreased ratios of arachidonic acid:eicosapentaenoic acid in plasma. Formula Y feeding did not alter eicosapentaenoic acid and docosahexaenoic acid levels in the plasma. In the erythrocyte, formula X feeding resulted in a threefold increase in eicosapentaenoic acid from mean baseline levels of 0.4 +/- 0.4% to a mean value of 1.2 +/- 0.9% at day 7. The formula X feeding decreased linoleic acid levels on days 7 and 14, whereas levels of arachidonic acid and docosahexaenoic acid remained constant. Formula Y feeding did not affect any of the parameters measured for erythrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of evening primrose oil, safflower oil and paraffin on plasma fatty acid levels in humans: Choice of an appropriate placebo for clinical studies on primrose oil

In a number of diseases, plasma levels of linoleic acid are normal or elevated while those of gamma-linolenic acid (18:3n-6, GLA) and further metabolites are below normal. Evening primrose oil (EPO), similar to safflower oil (SFO) except that it contains 8–9% of 18:3n-6, has been proposed as a therapeutic agent in these diseases, such as atopic eczema. There is arguments as to whether an appropriate placebo for clinical studies on EPO should be an inert material such as paraffin, or a linoleic acid — containing oil such as SFO. We have therefore compared in normal humans the effects on plasma fatty acids of administering EPO, SFO and paraffin for 10 days. Paraffin had no effect on any fatty acid in any fraction. EPO raised the level of 20:3n-6 (dihomo-gamma-linolenic acid, DGLA) the immediate metabolite of GLA but had no significant effect on arachidonic acid. In surprising contrast, SFO raised the levels of linoleic and of arachidonic acids, without raising those of DGLA. This suggests that linoleic acid may be rapidly converted to arachidonic acid by a tightly linked enzyme sequence: GLA, in contrast, may be rapidly converted to DGLA but then only slowly on to arachidonic acid. These results are consistent with recent in vitro observations by others on rat hepatocytes and human fibroblasts.

Linoleic acid‐induced endothelial cell injury: Role of membrane‐bound enzyme activities and lipid oxidation

High plasma levels of linoleic acid (18:2) may injure endothelial cells, resulting in decreased barrier function of the vascular endothelium. The effects of linoleic acid on endothelial barrier function (transendothelial movement of albumin), membrane-bound enzyme activities, and possible autooxidation of linoleic acid under experimental conditions were studied. The exposure of endothelial monolayers to 18:2 for 24 hr at 60, 90, and 120 microM fatty acid concentrations caused a significant increase in transendothelial movement of albumin, with maximum albumin transfer at 90 microM. Fatty acid treatment resulted in the increased appearance of cytosolic lipid droplets. Activities of the membrane-bound enzymes, angiotensin-converting enzyme (ACE), and Ca(2+)-ATPase increased steadily with increasing time of cell exposure to 90 microM 18:2, reaching significance at 24 hr. Treatment of endothelial cultures with up to 120 microM 18:2 did not cause cytotoxicity, as evidenced by a nonsignificant change in cellular release of [3H]-adenine. Incubation of 18:2-supplemented serum-containing culture media with 1000 microM 18:2 at 37 degrees C for up to 48 hr did not result in formation of autooxidation products. These results suggest that 18:2 itself, and not its oxidation products, plays a major role in disrupting endothelial barrier function.