Low Concentrations Of Arachidonic Acid Research Articles

Exogenous Arachidonic Acid Affects Fucoxanthin Biosynthesis and Photoprotection in Phaeodactylum tricornutum.

Fucoxanthin is an oxygenated carotenoid component that has been reported to play important roles in anti-oxidation, anti-obesity and anti-cancer in the human body. Fucoxanthin-chlorophyll protein (FCP) complexes participate in light harvesting and photoprotection in diatom. In order to better understand the change of fucoxanthin content and its role in photoprotection, the growth, fucoxanthin biosynthesis and photosynthetic phenotypes were studied in the diatom Phaeodactylum tricornutum under the treatment of exogenous arachidonic acid (AA). Our results demonstrated that even low concentration of AA at 0.1 mg/L strongly induced fucoxanthin accumulation in algal cells to a maximum of 1.1 mg/g dry weight (DW), which was 36.6% higher than that in the untreated ones. By principal component analysis (PCA), we also identified a close correlation between fucoxanthin accumulation and the expression of genes involved in fucoxanthin biosynthesis, especially phytoene synthase (PSY), suggesting that AA change the metabolism of fucoxanthin by inducing carotenoid metabolic enzymes at the transcriptional level. Furthermore, we found that the exogenous application of AA affected non-photochemical quenching (NPQ) and photoinhibition, which resulted from the changed diadinoxanthin (DD) and diatoxanthin (DT) cycle, and thus played an important role in photoprotection.

Syntaxin interacts with arachidonic acid to prevent diabetes mellitus

Syntaxin regulates pancreatic β cell mass and participates in insulin secretion by regulating insulin exocytosis. In addition, syntaxin 4 reduces IFNγ and TNF-α signaling via NF-ĸB in islet β-cells that facilitates plasma glucose sensing and appropriate insulin secretion. Arachidonic acid (AA) has potent anti-inflammatory actions and prevents the cytotoxic actions of alloxan and streptozotocin (STZ) against pancreatic β cells and thus, prevents the development of type 1 diabetes mellitus (induced by alloxan and STZ) and by virtue of its anti-inflammatory actions protects against the development of type 2 diabetes mellitus (DM) induced by STZ in experimental animals that are models of type 1 and type 2 DM in humans. AA has been shown to interact with syntaxin and thus, potentiate exocytosis. AA enhances cell membrane fluidity, increases the expression of GLUT and insulin receptors, and brings about its anti-inflammatory actions at least in part by enhancing the formation of its metabolite lipoxin A4 (LXA4). Prostaglandin E2 (PGE2), the pro-inflammatory metabolite of AA, activates ventromedial hypothalamus (VMH) neurons of the hypothalamus and inhibits insulin secretion leading to reduced glucose tolerance and decreases insulin sensitivity in the skeletal muscle and liver. This adverse action of PGE2 on insulin release and action can be attributed to its (PGE2) pro-inflammatory action and inhibitory action on vagal tone (vagus nerve and its principal neurotransmitter acetylcholine has potent anti-inflammatory actions). High fat diet fed animals have hypothalamic inflammation due to chronic elevation of PGE2. Patients with type 2 DM show low plasma concentrations of AA and LXA4 and elevated levels of PGE2. Administration of AA enhances LXA4 formation without altering or reducing PGE2 levels and thus, tilts the balance more towards anti-inflammatory events. These results suggest that administration of AA is useful in the prevention and management of DM by enhancing the action of syntaxin, increasing cell membrane fluidity, and reducing VMH inflammation. Docosahexaenoic acid (DHA) has actions like AA: it increases cell membrane fluidity; has anti-inflammatory actions by enhancing the formation of its anti-inflammatory metabolites resolvins, protectins and maresins; interacts with syntaxin and enhance exocytosis in general and of insulin. But the DHA content of cell membrane is lower compared to AA and its content in brain is significant. Hence, it is likely DHA is important in neurotransmitters secretion and regulating hypothalamic inflammation. It is likely that a combination of AA and DHA can prevent DM.

Multiassay nutritional metabolomics profiling of low vitamin A status versus adequacy is characterized by reduced plasma lipid mediators among lactating women in the Philippines: A pilot study

Low vitamin A (VA) status is common among lactating women in low-income countries. Lactation has substantial effects on mother's metabolism and VA is required in multiple biological processes, including growth, vision, immunity, and reproduction. The objective of this pilot study was to use metabolomics profiling to conduct a broad, exploratory assessment of differences in plasma metabolites associated with low VA status versus VA adequacy in lactating women. Plasma samples from lactating women who participated in a survey in Samar, Philippines, were selected from a cross-sectional study based on plasma retinol concentrations indicating low (VA–; n = 5) or adequate (VA+; n = 5) VA status (plasma retinol <0.8 or >1.05 µmol/L). The plasma results collected from 6 metabolomics assays (oxylipins, endocannabinoids, bile acids, primary metabolomics, biogenic amines, and lipidomics) were compared by group using liquid chromatography mass spectrometry. Twenty-eight metabolites were altered in the VA– versus VA+ status groups, with 24 being lipid mediators (P < .05). These lipid mediators included lower concentrations of arachidonic acid- and eicosapentaenoic acid-derived oxylipins, as well as lysophospholipids and sphingolipids, in the VA– group (P < .05). Chemical similarity enrichment analysis identified hydroxy-eicosatetraenoic acids, hydroxy-eicosapentaenoic acids, and dihydroxy-eicosatetraenoic acids as significantly altered oxylipin clusters (P < .0001, false discovery rate [FDR] P < .0001), as well as sphingomyelins, saturated lysophosphatidylcholines, phosphatidylcholines, and phosphatidylethanolamines (P < .001, FDR P < .01). The multiassay nutritional metabolomics profiling of low VA status compared with adequacy in lactating women was characterized by reduced lipid mediator concentrations. Future studies with stronger study designs and larger sample size are needed to confirm and validate these preliminary results.

Maternal and child fatty acid desaturase genotype as determinants of cord blood long-chain PUFA (LCPUFA) concentrations in the Seychelles Child Development Study.

Optimal maternal long-chain PUFA (LCPUFA) status is essential for the developing fetus. The fatty acid desaturase (FADS) genes are involved in the endogenous synthesis of LCPUFA. The minor allele of various FADS SNP have been associated with increased maternal concentrations of the precursors linoleic acid (LA) and α-linolenic acid (ALA), and lower concentrations of arachidonic acid (AA) and DHA. There is limited research on the influence of FADS genotype on cord PUFA status. The current study investigated the influence of maternal and child genetic variation in FADS genotype on cord blood PUFA status in a high fish-eating cohort. Cord blood samples (n 1088) collected from the Seychelles Child Development Study (SCDS) Nutrition Cohort 2 (NC2) were analysed for total serum PUFA. Of those with cord PUFA data available, maternal (n 1062) and child (n 916), FADS1 (rs174537 and rs174561), FADS2 (rs174575), and FADS1-FADS2 (rs3834458) were determined. Regression analysis determined that maternal minor allele homozygosity was associated with lower cord blood concentrations of DHA and the sum of EPA + DHA. Lower cord blood AA concentrations were observed in children who were minor allele homozygous for rs3834458 (β = 0·075; P = 0·037). Children who were minor allele carriers for rs174537, rs174561, rs174575 and rs3834458 had a lower cord blood AA:LA ratio (P < 0·05 for all). Both maternal and child FADS genotype were associated with cord LCPUFA concentrations, and therefore, the influence of FADS genotype was observed despite the high intake of preformed dietary LCPUFA from fish in this population.

Influence of fatty acid desaturase (FADS) genotype on maternal and child polyunsaturated fatty acids (PUFA) status and child health outcomes: a systematic review.

Polyunsaturated fatty acids (PUFA) are important during pregnancy for fetal development and child health outcomes. The fatty acid desaturase (FADS) genes also influence PUFA status, with the FADS genes controlling how much product (eg, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid) is metabolized from the precursor molecules linoleic acid and α-linolenic acid. The current review discusses the influence of FADS genotype on PUFA status of pregnant women, breast milk, and children, and also how FADS may influence child health outcomes. The Ovid Medline, Scopus, Embase, Cochrane Library, CINAHL Plus, PubMed and Web of Science databases were searched from their inception to September 2018. Eligible studies reported FADS genotype and blood concentrations of PUFA during pregnancy, in childhood, breast milk concentrations of PUFA or child health outcomes. In pregnant and lactating women, minor allele carriers have higher concentrations of linoleic acid and α-linolenic acid, and lower concentrations of arachidonic acid, in blood and breast milk, respectively. In children, FADS genotype influences PUFA status in the same manner and may impact child outcomes such as cognition and allergies; however, the direction of effects for the evidence to date is not consistent. Further studies are needed to further investigate associations between FADS and outcomes, as well as the diet-gene interaction.

The influence of maternal and child FADS genotype on cord blood polyunsaturated fatty acid (PUFA) concentrations

AbstractOptimal maternal polyunsaturated fatty acid (PUFA) status is essential for foetal development. The desaturase enzymes, encoded by the fatty acid desaturase (FADS) genes, are involved in the endogenous synthesis of long chain (LC)PUFA and influence maternal LCPUFA concentrations. The minor allele of various FADS SNPs has been associated with increased maternal concentrations of the precursors linoleic acid (LA) and α-linolenic acid (ALA), and lower concentrations of the LCPUFA arachidonic acid (AA) and docosahexaenoic acid (DHA); however, there is limited research to date on the influence of FADS genotype on cord PUFA status. The aim of the current study was to investigate the influence of maternal and child genetic variation on cord blood PUFA status in a high fish-eating cohort.Cord blood samples collected from mother-child pairs (n = 1088) taking part in the Seychelles Child Development Study (SCDS) Nutrition Cohort 2 (NC2) were analysed for total serum PUFA. Maternal (n = 1088) and child genotype (n = 592) were determined for the FADS SNPs rs174537, rs174561, rs174575, and rs3834458. Regression analysis determined associations between maternal and child FADS genotype and cord PUFA status. In all regression models, the major allele homozygote genotype for each SNP was used as the reference group.Directions of significant associations were as predicted. In mothers, the minor allele homozygote genotype for SNPs rs174537, rs174561 and rs3834458 was associated with lower cord DHA and lower total n-3 PUFA when compared to the major allele homozygous genotype (p &lt; 0.05 for all). The heterozygous genotype was associated with increased concentrations of LA compared to the reference genotype for rs174561 (p = 0.021) and rs383448 (p = 0.023). In children, the heterozygous genotype was associated with lower AA concentrations and lower cord n-6:n-3 ratio for all SNPs (p &lt; 0.05 for all) compared to those with the major allele homozygous genotype. A lower cord AA:LA ratio was also observed for children heterozygous for rs174547, rs174561 and rs174575 (p &lt; 0.05 for all). Contrary to expected, there were no associations between cord PUFA concentrations and child minor allele homozygous genotype.The current study indicates that variation in maternal and child FADS genotype influences cord PUFA concentrations, despite the high intake of preformed dietary LCPUFA from fish in this population. The sample size for minor allele homozygous children was likely too small to observe any statistically significant associations in the current analysis. Further research is needed to determine whether increased dietary intake can compensate for lower PUFA status as a result of FADS genotype.

Prostaglandins and Other Eicosanoids in Insects: Biosynthesis and Biological Actions.

This essay reviews the discoveries, synthesis, and biological significance of prostaglandins (PGs) and other eicosanoids in insect biology. It presents the most current – and growing – understanding of the insect mechanism of PG biosynthesis, provides an updated treatment of known insect phospholipase A2 (PLA2), and details contemporary findings on the biological roles of PGs and other eicosanoids in insect physiology, including reproduction, fluid secretion, hormone actions in fat body, immunity and eicosanoid signaling and cross-talk in immunity. It completes the essay with a prospectus meant to illuminate research opportunities for interested readers. In more detail, cellular and secretory types of PLA2, similar to those known on the biomedical background, have been identified in insects and their roles in eicosanoid biosynthesis documented. It highlights recent findings showing that eicosanoid biosynthetic pathway in insects is not identical to the solidly established biomedical picture. The relatively low concentrations of arachidonic acid (AA) present in insect phospholipids (PLs) (< 0.1% in some species) indicate that PLA2 may hydrolyze linoleic acid (LA) as a precursor of eicosanoid biosynthesis. The free LA is desaturated and elongated into AA. Unlike vertebrates, AA is not oxidized by cyclooxygenase, but by a specific peroxidase called peroxinectin to produce PGH2, which is then isomerized into cell-specific PGs. In particular, PGE2 synthase recently identified converts PGH2 into PGE2. In the cross-talks with other immune mediators, eicosanoids act as downstream signals because any inhibition of eicosanoid signaling leads to significant immunosuppression. Because host immunosuppression favors pathogens and parasitoids, some entomopathogens evolved a PLA2 inhibitory strategy activity to express their virulence.

Long-chain polyunsaturated fatty acid status in first-trimester pregnant women

Background: The beneficial effects of long-chain polyunsaturated fatty acid (LCPUFA) on maternal health have been widely investigated in pregnant women. First-trimester supplementation of LCPUFA has been reported to play a role in the inflammatory response, thus reducing a preterm birth and preeclampsia. However, there is a lack of studies investigating the blood concentration of LCPUFA in pregnant women in Indonesia. This study was conducted to evaluate the status of LCPUFA in first-trimester pregnant women in Jakarta, Indonesia.Methods: A descriptive study was conducted using the secondary data of 197 pregnant women in their first trimester who received antenatal care in Budi Kemuliaan Hospital during February 2012 to April 2015. Nutrient intake data were collected through interviews conducted using a semi-quantitative frequency food questionnaire (SQ-FFQ). Total concentrations of linoleic acid (LA), arachidonic acid (AA), alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) were measured using gas-chromatography/mass spectrometry (GC-MS). Statistical analysis of the data was conducted using SPSS 20.0.Results: Most subjects had deficient blood concentrations of LA (74.1%), AA (85.3%), ALA (76.6%), and DHA (73.1%). The median total concentrations of LA, AA, ALA, EPA, and DHA were as follows: 76.08%, 14.97%, 2.64%, 6.36%, and 1.18%, respectively. The median EPA+DHA level was 7.98%. A total of 38 women (19.3%) were classified as high-risk subjects based on the omega-3 index. No correlation was observed between total DHA+EPA concentration and birth weight (r=0.027, p=0.709). However, a significant difference was detected between the concentrations of LA, AA, and ALA and the maternal body mass index (p&lt;0.05).Conclusion: Most subjects had low intake and blood concentrations of LA, AA, ALA, EPA, and DHA in the first trimester of pregnancy.

The importance of dietary DHA and ARA in early life: a public health perspective.

Although the literature on the contribution of DHA and arachidonic acid (ARA) to fundamental metabolic functions in brain, immune and cardiovascular systems is extensive, there is a lack of consensus on the need for explicit recommendations on dietary intake for both DHA and ARA during the early years of life. This review takes a public health perspective with the objective of ensuring that recommendations protect the most vulnerable children worldwide. Most studies on the effects of DHA and ARA in early life have been undertaken in high-income countries and this is reflected in policy recommendations. Although breast milk is considered the gold standard and always contains DHA and ARA, there are proposals that infant formulas, especially follow-on formulas, do not need to be supplemented with these fatty acids. Complementary foods frequently have low concentrations of ARA and DHA and this is most significant in low-income countries where availability is also limited. Recent evidence shows that in developing countries, intakes of DHA and ARA during the age period 6-36 months are low and this relates to low national income. It is concluded that a continuum of DHA and ARA intake needs to be maintained during early life, a critical period of infant growth and development. For both infant and follow-on formulas, DHA and ARA should be mandatory at levels that are equivalent to breast milk. An optional recommendation may be limited to countries that can demonstrate evidence of adequate intakes of DHA and ARA during early life.

Licochalcones extracted from Glycyrrhiza inflata inhibit platelet aggregation accompanied by inhibition of COX-1 activity.

Licochalcones extracted from Glycyrrhiza inflata are known to have a variety of biological properties such as anti-inflammatory, anti-bacterial, and anti-tumor activities, but their action on platelet aggregation has not yet been reported. Therefore, in this study we investigated the effects of licochalcones on platelet aggregation. Collagen and U46619, a thromboxane A2 receptor agonist, caused rabbit platelet aggregation, which was reversed by pretreatment with licochalcones A, C and D in concentration-dependent manners. Among these compounds, licochalcone A caused the most potent inhibitory effect on collagen-induced platelet aggregation. However, the licochalcones showed marginal inhibitory effects on thrombin or ADP-induced platelet aggregation. In addition to rabbit platelets, licochalcone A attenuated collagen-induced aggregation in human platelets. Because licochalcone A also inhibited arachidonic acid-induced platelet aggregation and production of thromboxane A2 induced by collagen in intact platelets, we further examined the direct interaction of licochalcone A with cyclooxygenase (COX)-1. As expected, licochalcone A caused an inhibitory effect on both COX-1 and COX-2 in vitro. Regarding the effect of licochalcone A on COX-1 enzyme reaction kinetics, although licochalcone A showed a stronger inhibition of prostaglandin E2 synthesis induced by lower concentrations of arachidonic acid, Vmax values in the presence or absence of licochalcone A were comparable, suggesting that it competes with arachidonic acid at the same binding site on COX-1. These results suggest that licochalcones inhibit collagen-induced platelet aggregation accompanied by inhibition of COX-1 activity.

Arachidonic acid has protective effects on oxygen-glucose deprived astrocytes mediated through enhancement of potassium channel TREK-1 activity

Polyunsaturated fatty acids (PUFAs) have neuroprotective effects against ischemic brain diseases. The newly discovered potassium channel “TREK-1” is a promising target for therapies against neurodegeneration. Arachidonic acid (AA) is an n-6 PUFA, as well as a potent TREK-1 activator. We previously showed that TREK-1 is expressed at high levels in astrocytes. However, the effect of AA on astrocytes in ischemia remains unknown. Here, we assessed the effects of 3–30μM AA on astrocyte apoptosis, glutamate uptake, and expression of the astrocytic glutamate transporter 1 (GLT-1) and TREK-1 under different conditions. Under normal conditions, 3–30μM AA showed no effect on astrocytic apoptosis or TREK-1 expression, whereas glutamate uptake decreased significantly and its change paralleled the decreased expression of GLT-1. When astrocytes were subjected to 4h of oxygen-glucose deprivation (OGD), 10μM AA markedly alleviated OGD-induced cell death, recovering from 63.50±1.90% to 82.96±4.63% of the control value. AA also rescued the decreased glutamate uptake and increased mRNA, as well as protein levels of GLT-1 and TREK-1. Our results provide new evidence of a protective effect of AA on astrocytes under OGD conditions, suggesting that a low concentration of AA may protect against brain ischemic diseases.

An updated review of worldwide levels of docosahexaenoic and arachidonic acid in human breast milk by region.

We aimed to evaluate the DHA and arachidonic acid (AA) levels in human breast milk worldwide by country, region and socio-economic status. Descriptive review conducted on English publications reporting breast-milk DHA and AA levels. We systematically searched and identified eligible literature in PubMed from January 1980 to July 2015. Data on breast-milk DHA and AA levels from women who had given birth to term infants were included. Seventy-eight studies from forty-one countries were included with 4163 breast-milk samples of 3746 individuals. Worldwide mean levels of DHA and AA in breast milk were 0·37 (sd 0·11) % and 0·55 (sd 0·14) % of total fatty acids, respectively. The breast-milk DHA levels from women with accessibility to marine foods were significantly higher than those from women without accessibility (0·35 (sd 0·20) % v. 0·25 (sd 0·14) %, P<0·05). Data from the Asian region showed the highest DHA concentration but much lower AA concentration in breast milk compared with all other regions, independent of accessibility to marine foods. Comparison was made among Canada, Poland and Japan - three typical countries (each with sample size of more than 100 women) from different regions but all with high income and similar accessibility to fish/marine foods. The current review provides an update on worldwide variation in breast-milk DHA and AA levels and underlines the need for future population- or region-specific investigations.

Different Fatty Acids Compete with Arachidonic Acid for Binding to the Allosteric or Catalytic Subunits of Cyclooxygenases to Regulate Prostanoid Synthesis

Prostaglandin endoperoxide H synthases (PGHSs), also called cyclooxygenases (COXs), convert arachidonic acid (AA) to PGH2. PGHS-1 and PGHS-2 are conformational heterodimers, each composed of an (Eallo) and a catalytic (Ecat) monomer. Previous studies suggested that the binding to Eallo of saturated or monounsaturated fatty acids (FAs) that are not COX substrates differentially regulate PGHS-1 versus PGHS-2. Here, we substantiate and expand this concept to include polyunsaturated FAs known to modulate COX activities. Non-substrate FAs like palmitic acid bind Eallo of PGHSs stimulating human (hu) PGHS-2 but inhibiting huPGHS-1. We find the maximal effects of non-substrate FAs on both huPGHSs occurring at the same physiologically relevant FA/AA ratio of ∼20. This inverse allosteric regulation likely underlies the ability of PGHS-2 to operate at low AA concentrations, when PGHS-1 is effectively latent. Unlike FAs tested previously, we observe that C-22 FAs, including ω-3 fish oil FAs, have higher affinities for Ecat than Eallo subunits of PGHSs. Curiously, C-20 ω-3 eicosapentaenoate preferentially binds Ecat of huPGHS-1 but Eallo of huPGHS-2. PGE2 production decreases 50% when fish oil consumption produces tissue EPA/AA ratios of ≥0.2. However, 50% inhibition of huPGHS-1 itself is only seen with ω-3 FA/AA ratios of ≥5.0. This suggests that fish oil-enriched diets disfavor AA oxygenation by altering the composition of the FA pool in which PGHS-1 functions. The distinctive binding specificities of PGHS subunits permit different combinations of non-esterified FAs, which can be manipulated dietarily, to regulate AA binding to Eallo and/or Ecat thereby controlling COX activities.

Possible effects of repeated exposure to ibuprofen and acetaminophen on the intestinal immune response in young infants

There has been an exponential increase in the frequency of immune deviations in young children. Consequently, research investigating environmental causes for this increase has become a Public Health priority. We have summarized the experimental observations and epidemiological data that could link repeated acetaminophen and ibuprofen exposure in early infancy to this increase. Recent observations on the maturational immunity of the intestinal sub-mucosal lamina propria underscore indeed the importance of prostaglandins (PGE2s). PGE2 appearing at this sub-mucosal level is a product of arachidonic acid metabolism mediated by type-2 cyclooxygenase (COX-2) situated on the membrane of many immune cells. Moreover, it seems that acetaminophen – like ibuprofen – also carries a non-selective inhibitory action on peripheral COXs, besides its central action. This inhibitory action of acetaminophen on COX2 only relates to physiological, low arachidonic acid concentrations. This explains the difference in anti-inflammatory effects. The impact of repeated inhibition of mucosal PGE2 synthesis due to COX-inhibitor exposure on maturational immunity has been demonstrated in animal experiments. Repeatedly exposed young animals do not develop tolerance to food antigens and exhibit autoimmune deviations. Several recent epidemiological studies have also reported on the magnitude of acetaminophen and ibuprofen exposure in children and the increase in immune deviations, it is important to better understand the potential negative impact of repeated inhibitions of prostaglandin synthesis by COX2s during infancy. Since acetaminophen and ibuprofen are commonly administered analgesics and antipyretics, a well-designed prospective strategy for pharmacovigilance and -epidemiology of COX-inhibitor exposure in infancy is urgently needed.

Utilisation du paracétamol (acétaminophène) en néonatologie : (re)découverte d’un ancien principe actif

In neonates, paracetamol is mainly used for its analgesic action. This drug is actually preferred by neonatologists because of its broad therapeutic index. Recently, it has been demonstrated that paracetamol is also an anti-cyclooxygenase (COX) medication through its inhibitory action on the peroxidase arm of central and peripheral COX (Boutaud et al., 2002; Toussaint et al., 2010; Graham et al., 2013; Hinz et al., 2008; Hinz and Brune, 2011). As such, this drug interferes with the synthesis of prostaglandins. This inhibition of peroxidase is, however, limited to a low concentration of arachidonic acid (AA) (around 2μM, in vitro) when the plasmatic concentration of paracetamol is experimentally 10μM, actually within the same range as compared to the therapeutic concentrations in vivo. This may partly explain its low anti-inflammatory effect as compared to ibuprofen and indomethacin, which exert their inhibition on COX whatever the AA concentrations are. This new well-demonstrated action of paracetamol on peripheral COX-2 of intact cells could explain recent observations making this drug a potential alternative in treating patent ductus arteriosus. However, the higher dosages that have been claimed by some authors in this indication still remain to be validated. This inhibition that paracetamol shows on the physiological synthesis of prostaglandins E2 (PGE2) could also explain some long-term immune deviations because the physiological concentration of PGE2 is a well-known actor in the genesis of immune homeostasis in the submucosal area. Indeed, recent epidemiology studies have pointed out immune deviations in children repeatedly exposed to paracetamol earlier in life. Consequently, this is actually the new discovery of an old drug. From these new data on paracetamol, a more focused pharmacovigilance on the long-term effects of paracetamol repeatedly given in the early stage should be urgently initiated.

Interaction of Fatty Acid Genotype and Diet on Changes in Colonic Fatty Acids in a Mediterranean Diet Intervention Study

A Mediterranean diet increases intakes of n-3 and n-9 fatty acids and lowers intake of n-6 fatty acids. This can impact colon cancer risk as n-6 fatty acids are metabolized to proinflammatory eicosanoids. The purpose of this study was to evaluate interactions of polymorphisms in the fatty acid desaturase (FADS) genes, FADS1 and FADS2, and changes in diet on fatty acid concentrations in serum and colon. A total of 108 individuals at increased risk of colon cancer were randomized to either a Mediterranean or a Healthy Eating diet. Fatty acids were measured in both serum and colonic mucosa at baseline and after six months. Each individual was genotyped for four single-nucleotide polymorphisms in the FADS gene cluster. Linear regression was used to evaluate the effects of diet, genotype, and the diet by genotype interaction on fatty acid concentrations in serum and colon. Genetic variation in the FADS genes was strongly associated with baseline serum arachidonic acid (n-6) but serum eicosapentaenoic acid (n-3) and colonic fatty acid concentrations were not significantly associated with genotype. After intervention, there was a significant diet by genotype interaction for arachidonic acid concentrations in colon. Subjects who had all major alleles for FADS1/2 and were following a Mediterranean diet had 16% lower arachidonic acid concentrations in the colon after six months of intervention than subjects following the Healthy Eating diet. These results indicate that FADS genotype could modify the effects of changes in dietary fat intakes on arachidonic acid concentrations in the colon.

Polyunsaturated Fatty Acid Concentration Predicts Myelin Integrity in Early-Phase Psychosis

White matter (WM) abnormalities have been implicated in schizophrenia, yet the mechanisms underlying these abnormalities are not fully understood. Several lines of evidence suggest that polyunsaturated fatty acids (PUFAs) play a role in myelination, and there is substantial evidence documenting decreased PUFA concentrations in schizophrenia. We therefore hypothesized that lower membrane PUFA concentrations may be related to reduced WM integrity in schizophrenia and related disorders. In 30 male patients with a recent-onset psychotic disorder, erythrocyte membrane PUFA concentrations were assessed and diffusion tensor imaging was performed with voxelwise analysis. Lower total PUFA concentration was associated with lower fractional anisotropy (FA) throughout the corpus callosum and bilateral parietal, occipital, temporal and frontal WM (P < .05, corrected). Of the individual PUFAs, lower arachidonic acid concentration, and to a lesser extent, lower nervonic acid, linoleic acid, and docosapentaenoic acid concentration were significantly associated with lower FA. PUFA concentrations were inversely associated with radial diffusivity but showed little association with axial diffusivity. Greater severity of negative symptoms was associated with lower nervonic acid concentration and lower FA values. Membrane PUFA concentrations appear to be robustly related to brain WM integrity in early phase psychosis. These findings may provide a basis for studies to investigate the effects of PUFA supplementation on WM integrity and associated symptomatology in early psychosis.

STIM and Orai proteins and the non-capacitative ARC channels

The ARC channel is a small conductance, highly Ca²⁺-selective ion channel whose activation is specifically dependent on low concentrations of arachidonic acid acting at an intracellular site. They are widely distributed in diverse cell types where they provide an alternative, store-independent pathway for agonist-activated Ca²⁺ entry. Although biophysically similar to the store-operated CRAC channels, these two conductances function under distinct conditions of agonist stimulation, with the ARC channels providing the predominant route of Ca²⁺ entry during the oscillatory signals generated at low agonist concentrations. Despite these differences in function, like the CRAC channel, activation of the ARC channels is dependent on STIM1, but it is the pool of STIM1 that constitutively resides in the plasma membrane that is responsible. Similarly, both channels are formed by Orai proteins but, whilst the CRAC channel pore is a tetrameric assembly of Orai1 subunits, the ARC channel pore is formed by a heteropentameric assembly of three Orai1 subunits and two Orai3 subunits. There is increasing evidence that the activity of these channels plays a critical role in a variety of different cellular activities.

First Report of Transheterozygosity in a Patient with An Inherited Platelet Bleeding Disorder Due to Mutations in the Thromboxane A2 Receptor (TBXA2R) and cyclooxygenase1 (PTGS1),

Abstract 3260Platelet aggregation by thromboxane (TBXA2) stimulation of its G protein-coupled receptor TXA2R is initiated after conversion of arachidonic acid (AA) into prostaglandin H2 (PGH2) by cyclooxygenase1 (PTGS1) and subsequently by conversion of PGH2 into TXA2 by thromboxane synthase (TBXAS1). Hirata et al (JCI, 1994) reported the first TBXA2R mutation that resulted in reduced platelet responses to U46619 and low AA concentrations in subjects with a heterozygous R60L mutation. This functional defect in combination with mild clinical bleeding problems was only described for the one patient that was homozygous for this mutation. A second TBXA2 patient with an obvious bleeding diathesis carried a heterozygous D304N mutation but it was reported that this variant by itself could not explain the bleeding phenotype as other family members heterozygous for D304N presented with abnormal aggregation responses but no bleeding problems (Mumford, Blood, 2010). Functional SNPs in PTGS1 were described in pharmacogenetic studies including the L237M variant with 50% reduced COX1 metabolic activity but its effect on platelet function was not studied (Lee CR, Pharmacogenet Genomics, 2007).We here describe a 6-year old patient with ecchymosis, easy bruising and important post-traumatic bleeding complications after adenotonsillectomy and circumcision. The boy presents with normal coagulation parameters, normal platelet count and MPV, structurally normal platelets, normal ATP secretion by collagen, and the PFA100 closure time was normal for Col/Epi and mildly prolonged for Col/ADP. Platelet aggregation studies further showed an absent response to 1 mM AA as determined on different occasions, a reduced but not absent response to U46619 and a normal activation with ADP, ristocetin and Horm collagen. His parents and sister presented with increased sensitivity for ecchymoses but none had severe clinical bleeding problems and their platelets showed normal aggregation responses except for the father and sister with a reduced though not absent response to AA. Thromboxane B2 formation was determined and found to be normal in basal (plasma) and maximal stimulated (serum) conditions. In contrast, TXB2 levels were decreased after activation with U46619 for the patient but also for the father and sister compared to the control or mother. Activation with AA also resulted in reduced TXB2 levels for the patient and mildly reduced levels for all other family member compared to controls. This strongly suggests the presence of an autosomal recessive disorder. The TBXAS1, PTGS1 and TBXA2R genes were sequenced for the patient and we identified two heterozygous mutations in separate genes being R60H in TXBA2R and the functional L237M variant in PTGS1. Interestingly, his mother carried the L237M variant while R60H was present in father and sister with similar functional platelet defects as earlier described for the other heterogenous TBXA2R mutations but no clinical bleeding symptoms. To our knowledge, this is the first case of transheterozygosity for mutations explaining an autosomal recessive bleeding disorder. We hypothesize that this pattern of inheritance might be more common than expected and therefore this possibility should be taken into account when analyzing patients in the future using exome or genome wide sequencing platforms. Disclosures:No relevant conflicts of interest to declare.

Arachidonic Acid Randomizes Endothelial Cell Motion and Regulates Adhesion and Migration

Cell adhesion and migration are essential for the evolution, organization, and repair of living organisms. An example of a combination of these processes is the formation of new blood vessels (angiogenesis), which is mediated by a directed migration and adhesion of endothelial cells (ECs). Angiogenesis is an essential part of wound healing and a prerequisite of cancerous tumor growth. We investigated the effect of the amphiphilic compound arachidonic acid (AA) on EC adhesion and migration by combining live cell imaging with biophysical analysis methods. AA significantly influenced both EC adhesion and migration, in either a stimulating or inhibiting fashion depending on AA concentration. The temporal evolution of cell adhesion area was well described by a two-phase model. In the first phase, the spreading dynamics were independent of AA concentration. In the latter phase, the spreading dynamics increased at low AA concentrations and decreased at high AA concentrations. AA also affected EC migration; though the instantaneous speed of individual cells remained independent of AA concentration, the individual cells lost their sense of direction upon addition of AA, thus giving rise to an overall decrease in the collective motion of a confluent EC monolayer into vacant space. Addition of AA also caused ECs to become more elongated, this possibly being related to incorporation of AA in the EC membrane thus mediating a change in the viscosity of the membrane. Hence, AA is a promising non-receptor specific regulator of wound healing and angiogenesis.