胰高血糖素样肽l对脂多糖诱导的血管内皮细胞炎性反应的影响

目的:探讨胰高血糖素样肽l(glucagon like peptide 1,GLP-1)对脂多糖(1ipopolysaccharide,LPS)诱导的血管内皮细胞(VEC)炎性反应的影响。方法:以体外培养的人动脉VEC为研究模型,将细胞分为四组(对照组、LPS刺激组、LPS+GLP-1组、GLP-1组),Rhodamin-Phalloidin检测肌动蛋白骨架F-actin分布,用苏木素-伊红(HE)染色观察细胞间连接的形态特征,用示踪剂Rhodamine B isothiocyanate-Dextran检测VECs单层通透性变化改变,酶联免疫吸附实验检测细胞分泌白介素(IL)-6和IL-8的变化。结果:GLP-1(100 nM)可减少LPS(1μg/mL)刺激后细胞肌动蛋白骨架F-actin应力纤维的形成,并抑制LPS刺激后细胞间连接的中断。Rhodamine B isothiocyanate-Dextran细胞通透性检测结果显示:GLP-1可明显降低LPS刺激引起的VEC通透性增加[由(2.57±0.19)×10-5cm/s降至(2.10±0.18)×10-5cm/s,P0.05]。此外,GLP-1可抑制LPS刺激后VEC中炎性细胞因子IL-6和IL-8的表达[分别由(42130±6522)pg/ml降至(27478±5096)pg/ml和(18376±1561)pg/ml降至(14414±927)pg/ml,均P0.05]。结论:GLP-1可对抗LPS刺激引起的VEC炎症反应和细胞通透性增加,改善LPS诱导的内皮细胞炎性损伤。     

胰高血糖素样肽1对脂多糖诱导的血管内皮细胞炎性反应的影响

目的：探讨胰高血糖素样肽1（glucagon like peptide 1,GLP-1）对脂多糖（1ipopolysaccharide,LPS）诱导的血管内皮细胞（VEC）炎性反应的影响。方法：以体外培养的人动脉VEC为研究模型,将细胞分为四组（对照组、LPS刺激组、LPS±GLP-1组、GLP-1组）,Rhodamin-Phalloidin检测肌动蛋白骨架F-actin分布,用苏木素-伊红（HE）染色观察细胞间连接的形态特征,用示踪剂Rhodamine Bisothiocyanate-Dextran检测VECs单层通透性变化改变,酶联免疫吸附实验检测细胞分泌白介素（IL）-6和IL-8的变化。结果：GLP-1（100nM）可减少LPS（1μg／mL）刺激后细胞肌动蛋白骨架F-actin应力纤维的形成,并抑制LPS刺激后细胞间连接的中断。Rhodamine B isothiocyanate-Dextran细胞通透性检测结果显示：GLP-1可明显降低LPS刺激引起的VEC通透性增加[由（2．57±0．19）×10^-5cm／s降至（2．10±0．18）×10^-5cm／s,P〈0．05]。此外,GLP-1可抑制LPS刺激后VEC中炎性细胞因子IL-6和IL-8的表达[分别由（42130±6522）pg／ml降至（27478±5096）pg／ml和（18376±1561）pg／ml降至（14414±927）pg／ml,均P〈0．05]。结论：GLP-1可对抗LPS刺激引起的VEC炎症反应和细胞通透性增加．改善LPS诱导的内皮细胞炎性损伤。     

Combination of Omega-3 Fatty Acids,Lithium, and Aripiprazole Reduces Oxidative Stress in Brain of Mice with Mania

Manic episode in bipolar disorder (BD) was evaluated in the present study with supplementation of omega-3 fatty acids in combination with aripiprazole and lithium on methylphenidate (MPD)-induced manic mice model. Administration of MPD 5 mg/kg bw intraperitoneally (i.p.) caused increase in oxidative stress in mice brain. To retract this effect, supplementation of omega-3 fatty acids 1.5 ml/kg (p.o.), aripiprazole 1.5 mg/kg bw (i.p.), and lithium 50 mg/kg bw (p.o) were given to mice. Omega-3 fatty acids alone and in combination with aripiprazole- and lithium-treated groups significantly reduced the levels of superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation products (thiobarbituric acid reactive substances) in the brain. MPD treatment significantly decreased the reduced glutathione (GSH) level and glutathione peroxidase (GPx) activity, and they were restored by supplementation of omega-3 fatty acids with aripiprazole and lithium. There is no remarkable difference in the effect of creatine kinase (CK) activity between MPD-induced manic model and the treatment groups. Therefore, our results demonstrate that oxidative stress imbalance and mild insignificant CK alterations induced by administration of MPD can be restored back to normal physiological levels through omega-3 fatty acids combined with lithium and aripiprazole that attributes to effective prevention against mania in adult male Swiss albino mice.     

Protective Effect of Selenomethionine on Aflatoxin B1-Induced Oxidative Stress in MDCK Cells

AFB1 is a mycotoxin which exerts their cytotoxicity through increasing oxidative damage in target organ. Kidney is one of target organs vulnerable to damage caused by AFB1. In this study, Madin-Darby canine kidney (MDCK) cells were used to evaluate the AFB1-induced cell damage by the MTT assay. The results revealed that the toxic effect of AFB1 on MDCK cells is both dose and time dependent. Half maximal toxic concentration (IC₅₀) was noted at 0.25 μg/ml of AFB1. Further, protective effect of six different concentrations (0.2, 0.8, 1, 2, 4, and 8 μM) of selenomethionine (SeMet) was observed against 0.25 μg/ml of AFB1-induced damage. The results showed that 0.25 μg/ml of AFB1 caused significant increase in oxidative stress, which was demonstrated by significant increase of malondialdehyde (MDA) level, reduction of intracellular GSH level, as well as GPX1 activity and mRNA level in MDCK cells when compared with control. SeMet protected the cells from AFB1-induced oxidative damage in a dose-dependant manner. Good protection could be achieved between 1 and 4 μM of concentration. Amid this range, MDA level significantly decreased while intracellular GSH level and GPX1 activity in addition to mRNA level significantly increased. Moreover, cell viability was significantly improved. It could be concluded that SeMet is a potential antioxidative agent to alleviate AFB1-induced oxidative stress.     

Individual Variation in Lipidomic Profiles of Healthy Subjects in Response to Omega-3 Fatty Acids

Introduction

Conflicting findings in both interventional and observational studies have resulted in a lack of consensus on the benefits of ω3 fatty acids in reducing disease risk. This may be due to individual variability in response. We used a multi-platform lipidomic approach to investigate both the consistent and inconsistent responses of individuals comprehensively to a defined ω3 intervention.

Methods

The lipidomic profile including fatty acids, lipid classes, lipoprotein distribution, and oxylipins was examined multi- and uni-variately in 12 healthy subjects pre vs. post six weeks of ω3 fatty acids (1.9 g/d eicosapentaenoic acid [EPA] and 1.5 g/d docosahexaenoic acid [DHA]).

Results

Total lipidomic and oxylipin profiles were significantly different pre vs. post treatment across all subjects (p=0.00007 and p=0.00002 respectively). There was a strong correlation between oxylipin profiles and EPA and DHA incorporated into different lipid classes (r²=0.93). However, strikingly divergent responses among individuals were also observed. Both ω3 and ω6 fatty acid metabolites displayed a large degree of variation among the subjects. For example, in half of the subjects, two arachidonic acid cyclooxygenase products, prostaglandin E₂ (PGE₂) and thromboxane B2 (TXB₂), and a lipoxygenase product, 12-hydroxyeicosatetraenoic acid (12-HETE) significantly decreased post intervention, whereas in the other half they either did not change or increased. The EPA lipoxygenase metabolite 12-hydroxyeicosapentaenoic acid (12-HEPE) varied among subjects from an 82% decrease to a 5,000% increase.

Conclusions

Our results show that certain defined responses to ω3 fatty acid intervention were consistent across all subjects. However, there was also a high degree of inter-individual variability in certain aspects of lipid metabolism. This lipidomic based phenotyping approach demonstrated that individual responsiveness to ω3 fatty acids is highly variable and measurable, and could be used as a means to assess the effectiveness of ω3 interventions in modifying disease risk and determining metabolic phenotype.     

A Combined Supplementation of Omega-3 Fatty Acids and Micronutrients (Folic Acid,Vitamin B12) Reduces Oxidative Stress Markers in a Rat Model of Pregnancy Induced Hypertension

Objectives

Our earlier studies have highlighted that an altered one carbon metabolism (vitamin B₁₂, folic acid, and docosahexaenoic acid) is associated with preeclampsia. Preeclampsia is also known to be associated with oxidative stress and inflammation. The current study examines whether maternal folic acid, vitamin B₁₂ and omega-3 fatty acid supplementation given either individually or in combination can ameliorate the oxidative stress markers in a rat model of pregnancy induced hypertension (PIH).

Materials and Methods

Pregnant Wistar rats were assigned to control and five treatment groups: PIH; PIH + vitamin B₁₂; PIH + folic acid; PIH + Omega-3 fatty acids and PIH + combined micronutrient supplementation (vitamin B₁₂ + folic acid + omega-3 fatty acids). L-Nitroarginine methylester (L-NAME; 50 mg/kg body weight/day) was used to induce hypertension during pregnancy. Blood Pressure (BP) was recorded during pregnancy and dams were dissected at d20 of gestation.

Results

Animals from the PIH group demonstrated higher (p<0.01 for both) systolic and diastolic BP; lower (p<0.01) pup weight; higher dam plasma homocysteine (p<0.05) and dam and offspring malondialdehyde (MDA) (p<0.01), lower (p<0.05) placental and offspring liver DHA and higher (p<0.01) tumor necrosis factor–alpha (TNF–ά) levels as compared to control. Individual micronutrient supplementation did not offer much benefit. In contrast, combined supplementation lowered systolic BP, homocysteine, MDA and placental TNF-ά levels in dams and liver MDA and protein carbonyl in the offspring as compared to PIH group.

Conclusion

Key constituents of one carbon cycle (folic acid, vitamin B₁₂ and DHA) may play a role in reducing oxidative stress and inflammation in preeclampsia.     

Effect of Vitamin E and Polyunsaturated Fatty Acids on Cryopreserved Sperm Quality in Bos taurus Bulls Under Testicular Heat Stress

Taurine bulls are highly susceptible to heat stress, leading to increased oxidative stress (OS) and impaired sperm viability. Polyunsaturated fatty acids (PUFAs) supplementation can be an alternative to improve semen quality, which also results in more sperm susceptibility to lipid peroxidation. Moreover, this deleterious effect can be exacerbated in animals affected by heat stress. Vitamin E is a key antioxidant that counteracts lipid peroxidation of sperm membrane caused by OS. Thus, combining PUFAs with vitamin E may improve sperm quality. In this context, this study aimed to evaluate the effect of interaction between PUFAs and vitamin E on sperm quality in Bos taurus bulls under testicular heat stress. Sixteen taurine bulls under testicular heat stress were randomly assigned in four groups: Control, Vitamin E, PUFA, and PUFA?+?Vitamin E. All groups lasted for 60 days. Samples were cryopreserved/thawed and analyzed for motility variables (CASA), membrane and acrosome integrity, mitochondrial activity, susceptibility to oxidative stress, DNA integrity, and sperm-binding capacity. Results showed that vitamin E had a beneficial effect on some sperm characteristics, whereas PUFA supplementation had an adverse effect when the two treatments were evaluated separately. Finally, the association between PUFAs and vitamin E did not improve sperm quality.     

Effect of Oxidative Stress on the Junctional Proteins of Cultured Cerebral Endothelial Cells

Summary 1. There is increasing evidence that the cerebral endothelium and the blood–brain barrier (BBB) plays an important role in the oxidative stress-induced brain damage. The aim of the present study was to investigate the role of interendothelial junctional proteins in the BBB permeability increase induced by oxidative stress.2. For the experiments, we have used cultured cerebral endothelial cells exposed to hypoxia/reoxygenation or treated with the redox cycling quinone 2,3-Dimethoxy-1,4-naphthoquinone (DMNQ) in the presence or absence of glucose. The expression of junctional proteins and activation of mitogen activated protein kinases (MAPK) was followed by Western-blotting, the interaction of junctional proteins was investigated using coimmunoprecipitation.3. Oxidative stress induces a downregulation of the tight junction protein occludin expression which is more pronounced in the absence of glucose. Furthermore, oxidative stress leads to disruption of the cadherin--catenin complex and an activation of extracellular signal-regulated kinase (ERK1/2), which is more intense in the absence of glucose.4. We have shown that one of the causes of the BBB breakdown is probably the structural alteration of the junctional complex caused by oxidative stress, a process in which ERK1/2 may play an important role.This revised article was published online in May 2005 with a February 2005 cover date.     

氧化应激及炎症反应在Graves病中的研究进展

Graves病是一种常见器官特异性自身免疫性疾病,是甲状腺功能亢进症中最常见的原因.Graves眼病是Graves病的常见表现之一.Graves病的发病机制涉及遗传因素、环境因素及自身免疫因素三个方面,一般认为Graves病是以遗传易感因素为背景,在感染、精神等因素作用下,诱发体内的自身免疫功能紊乱,但是Graves病的确切发病机制及病理进展目前仍不清楚.有研究发现炎症反应和氧化应激产物在Graves病的发病及病理进展中起重要作用.氧化应激及炎症反应在Graves病及Graves眼病的发生发展中共同作用,互为因果.因此,抗氧化应激及抗炎症反应药物对治疗Graves病中有广泛的应用前景.     

Trans Fatty Acids Enhanced Beta-Amyloid Induced Oxidative Stress in Nerve Growth Factor Differentiated PC12 Cells

The effects of trans fatty acids, elaidic acid (trans-9, C18:1) and linoelaidic acid (trans-9, trans-12 C18:2), at 20 or 40 μM in nerve growth factor differentiated PC12 cells with or without beta-amyloid peptide (Aβ) were examined. Elaidic acid treatment alone did not affect cell viability and oxidative injury associated markers (P > 0.05). However, co-treatments of elaidic acid and Aβ led to more reduction in mitochondrial membrane potential (MMP) and Na⁺-K⁺-ATPase activity, and more increase in DNA fragmentation and 8-hydroxydeoxyguanosine (8-OHdG) production than Aβ treatment alone (P < 0.05). Linoelaidic acid alone exhibited apoptotic and oxidative effects in cells via decreasing MMP and Na⁺-K⁺-ATPase activity, increasing reactive oxygen species (ROS) level, lowering glutathione content and glutathione peroxidase (GPX) activity (P < 0.05). The co-treatments of linoelaidic acid with Aβ further enhanced oxidative damage via enhancing the generation of ROS, nitrite oxide and 8-OHdG, elevating caspase-3, caspase-8 and nitric oxide synthase activities, as well as declining GPX, catalase and superoxide dismutase activities (P < 0.05). These results suggested that the interaction of linoelaidic acid and Aβ promoted oxidative stress and impaired mitochondrial functions in neuronal cells.     

Omega 3 Fatty Acids Supplementation and Oxidative Stress in HIV-Seropositive Patients. A Clinical Trial

HIV-seropositive patients show high incidence of coronary heart disease and oxidative stress has been described as relevant key in atherosclerosis development. The aim of this study was to assess the effect of omega 3 fatty acids on different markers of oxidative stress in HIV-seropositive patients. We performed a randomized parallel controlled clinical trial in The Instituto Mexicano del Seguro Social, a public health hospital. 70 HIV-seropositive patients aged 20 to 55 on clinical score A1, A2, B1 or B2 receiving highly active antiretroviral therapy (HAART) were studied. They were randomly assigned to receive omega 3 fatty acids 2.4 g (Zonelabs, Marblehead MA) or placebo for 6 months. At baseline and at the end of the study, anthropometric measurements, lipid profile, glucose and stress oxidative levels [nitric oxide catabolites, lipoperoxides (malondialdehyde plus 4-hydroxialkenals), and glutathione] were evaluated. Principal HAART therapy was EFV/TDF/FTC (55%) and AZT/3TC/EFV (15%) without difference between groups. Treatment with omega 3 fatty acids as compared with placebo decreased triglycerides (-0.32 vs. 0.54 mmol/L; p = 0.04), but oxidative stress markers were not different between groups.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT02041520","term_id":"NCT02041520"}}NCT02041520     

剪应力和周向应变联合作用下血管内皮细胞内自由Ca^2＋响应

机械力调节血管内皮细胞功能。Ca2 在机械力信号转导中扮演了重要的角色。本文研究剪应力和周向应变联合作用下血管内皮细胞内自由Ca2 浓度的变化规律,结果表明,在生理周向应变条件(小于15%)下,同时暴露于剪应力和周向应变的细胞内自由Ca2 浓度变化更依赖于剪应力大小而非周向应变的大小,Ca2 浓度升高主要是胞外Ca2 内流引起的。     

Omega-3 Essential Fatty Acids Modulate Initiation and Progression of Neurodegenerative Disease

The significance of the selective enrichment in omega-3 essential fatty acids in photoreceptors and synaptic membranes of the nervous system has remained, until recently, incompletely understood. While studying mechanisms of cell survival in neural degeneration, we discovered a docosanoid synthesized from unesterified docosahexaenoic acid (DHA) by a 15-lipoxygenase (15-LOX), which we called neuroprotectin D1 (NPD1; 10R,17S-dihydroxy-docosa-4Z,7Z,11E,13E,15E,19Z hexaenoic acid). This lipid mediator is a docosanoid because it is derived from the 22 carbon (22C) precursor DHA, unlike eicosanoids, which are derived from the 20 carbon (20C) arachidonic acid (AA) family member of essential fatty acids. We discovered that NPD1 is promptly made in response to oxidative stress, as a response to brain ischemia–reperfusion, and in the presence of neurotrophins. NPD1 is neuroprotective in experimental brain damage, in oxidative-stressed retinal pigment epithelial (RPE) cells, and in human brain cells exposed to amyloid-β (Aβ) peptides. We thus envision NPD1 as a protective sentinel, one of the very first defenses activated when cell homeostasis is threatened by imbalances in normal neural function. We provide here, in three sections, recent experimental examples that highlight the specificity and potency of NPD1 spanning beneficial bioactivity during initiation and early progression of neurodegeneration: (1) during retinal signal phototransduction, (2) during brain ischemia–reperfusion, and (3) in Alzheimer's disease (AD) and stressed human brain cell models of AD. From this experimental evidence, we conclude that DHA-derived NPD1 regulation targets upstream events of brain cell apoptosis, as well as neuro-inflammatory signaling, promoting and maintaining cellular homeostasis, and restoring neural and retinal cell integrity.     

Neurorestorative Targets of Dietary Long-Chain Omega-3 Fatty Acids in Neurological Injury

Long-chain omega-3 polyunsaturated fatty acids (LC-O3PUFAs) exhibit therapeutic potential for the treatment and prevention of the neurological deficits associated with spinal cord injury (SCI). However, the mechanisms implicated in these protective responses remain unclear. The objective of the present functional metabolomics study was to identify and define the dominant metabolic pathways targeted by dietary LC-O3PUFAs. Sprague-Dawley rats were fed rodent purified chows containing menhaden fish oil-derived LC-O3PUFAs for 8 weeks before being subjected to sham or spinal cord contusion surgeries. We show, through untargeted metabolomics, that dietary LC-O3PUFAs regulate important biochemical signatures associated with amino acid metabolism and free radical scavenging in both the injured and sham-operated spinal cord. Of particular significance, the spinal cord metabolome of animals fed with LC-O3PUFAs exhibited reduced glucose levels (?48 %) and polar uncharged/hydrophobic amino acids (less than ?20 %) while showing significant increases in the levels of antioxidant/anti-inflammatory amino acids and peptides metabolites, including β-alanine (+24 %), carnosine (+33 %), homocarnosine (+27 %), kynurenine (+88 %), when compared to animals receiving control diets (p?N-acetylglutamate (+43 %) and acetyl CoA levels (+27 %), respectively. Interestingly, this dietary intervention resulted in a global correction of the pro-oxidant metabolic profile that characterized the SCI-mediated sensorimotor dysfunction. In summary, the significant benefits of metabolic homeostasis and increased antioxidant defenses unlock important neurorestorative pathways of dietary LC-O3PUFAs against SCI.     

The Vascular Endothelial Growth Factor Inhibitors Ranibizumab and Aflibercept Markedly Increase Expression of Atherosclerosis-Associated Inflammatory Mediators on Vascular Endothelial Cells

Introduction

Recent studies have suggested that the VEGF inhibitors, Ranibizumab and Aflibercept may be associated with an excess of cardiovascular events, potentially driven by increasing atheroma instability, leading to plaque rupture and clinical events. Inflammation plays a key role in the progression of atherosclerotic plaque and particularly conversion to an unstable phenotype. Here, we sought to assess the in vitro effects of these drugs on the expression of key inflammatory mediators on endothelial cells.

Methods

Human coronary artery endothelial cells were co-incubated for 16h with Ranibizumab (0.11nM) or Aflibercept (0.45nM), as determined by each drug’s peak serum concentration (Cmax). Expression at protein (ELISA) and gene (RT-PCR) level of inflammatory chemokines CCL2, CCL5 and CXC3L1 as well as gene expression for the cell adhesion molecules VCAM-1, ICAM-1 and the key NF-κb protein p65 was assessed. VEGF-A protein levels were also determined.

Results

Both drugs significantly increased chemokine, cell adhesion molecule (CAM) and p65 expression, while decreasing VEGF-A protein secretion. At equivalent Cmax concentrations, Aflibercept was significantly more pro-inflammatory than Ranibizumab. Reduction of secreted VEGF-A levels significantly attenuated inflammatory effects of both drugs, whereas blockade of the VEGF-A receptor or silencing of VEGF-A gene synthesis alone had no effect, suggesting that binding of drug to secreted VEGF-A is crucial in promoting inflammation. Finally, blockade of Toll-like receptor 4 significantly reduced inflammatory effects of both drugs.

Conclusion

We demonstrated here, for the first time, that both drugs have potent pro-inflammatory effects, mediated via activation of Toll-like receptor 4 on the endothelial cell surface by drug bound to VEGF-A. Further studies are required to investigate whether these effects are also seen in vivo.     

氧化应激诱导内皮细胞凋亡microRNA表达改变的研究

目的:研究氧化应激诱导的内皮细胞micro RNA的表达变化。方法:ECM(Endothelial Cell Medium)培养人脐静脉内皮细胞,利用不同浓度双氧水(0μmol/L,200μmol/L,500μmol/L,800μmol/L)刺激24小时后应用流式细胞术检测其凋亡水平。提取细胞总RNA,利用实时定量PCR(Quantitive real-time PCR;q RT-PCR)检测micro RNA表达量变化,并利用生物信息学软件预测可能的靶基因。结果:加入不同浓度双氧水处理24 h后的内皮细胞总凋亡率均显著高于对照组,200μmol/L、500μmol/L和800μmol/L组的凋亡率分别为(13.31%vs 4.75%,35.9%vs 4.75%,89.75%vs 4.75%,P0.01)。200μmol/L的双氧水处理内皮细胞后,micro RNA的表达出现了明显的改变。其中mi R-92a、mi R-126的表达明显下调(P0.05),mi R-181a、mi R-217、mi R-34a和mi R-320的表达明显上调(P0.05)。靶基因预测显示mi R-320、mi R-92a可能调控多个和内皮细胞凋亡相关的基因表达。结论:在氧化应激诱导的内皮细胞凋亡中,mi RNA表达发生改变并可能参与调控内皮细胞功能。     

Selective Enrichment of Omega-3 Fatty Acids in Oils by Phospholipase A1

Omega fatty acids are recognized as key nutrients for healthier ageing. Lipases are used to release ω-3 fatty acids from oils for preparing enriched ω-3 fatty acid supplements. However, use of lipases in enrichment of ω-3 fatty acids is limited due to their insufficient specificity for ω-3 fatty acids. In this study use of phospholipase A1 (PLA1), which possesses both sn-1 specific activity on phospholipids and lipase activity, was explored for hydrolysis of ω-3 fatty acids from anchovy oil. Substrate specificity of PLA1 from Thermomyces lenuginosus was initially tested with synthetic p-nitrophenyl esters along with a lipase from Bacillus subtilis (BSL), as a lipase control. Gas chromatographic characterization of the hydrolysate obtained upon treatment of anchovy oil with these enzymes indicated a selective retention of ω-3 fatty acids in the triglyceride fraction by PLA1 and not by BSL. ¹³C NMR spectroscopy based position analysis of fatty acids in enzyme treated and untreated samples indicated that PLA1 preferably retained ω-3 fatty acids in oil, while saturated fatty acids were hydrolysed irrespective of their position. Hydrolysis of structured triglyceride,1,3-dioleoyl-2-palmitoylglycerol, suggested that both the enzymes hydrolyse the fatty acids at both the positions. The observed discrimination against ω-3 fatty acids by PLA1 appears to be due to its fatty acid selectivity rather than positional specificity. These studies suggest that PLA1 could be used as a potential enzyme for selective concentrationof ω-3 fatty acids.