Growth reduction in glioma cells after treatment with tetradecylthioacetic acid: changes in fatty acid metabolism and oxidative status

During aerobic metabolism, a small amount of partially reduced oxygen is produced, yielding reactive oxygen species (ROS). Peroxisomes and mitochondria are major contributors to cellular ROS production, which is normally balanced by consumption by antioxidants. The fatty acid analogue tetradecylthioacetic acid (TTA) promotes mitochondrial and peroxisomal proliferation, and may induce oxidative stress and change the growth potential of cancer cells. In the present study, we found that TTA reduced [(3)H]thymidine incorporation in the glioma cell lines BT4Cn (rat), D54Mg (human), and GaMg (human) in a dose- and time-dependent manner. The 50% inhibitory TTA doses were approximately 125 microM for BT4Cn and D54Mg cells and 40 microM for GaMg cells after 4 days. alpha-Tochopherol counteracted this inhibition in GaMg cells. TTA enhanced the oxidation of [1-(14)C]palmitic acid, which could be explained by stimulation of enzymes involved in peroxisomal (fatty acyl-CoA oxidase) and/or mitochondrial (carnitine palmitoyltransferase) fatty acid oxidation. The glutathione content and the activities of glutathione peroxidase, glutathione reductase, and glutathione S-transferase were differentially affected. Increased malondialdehyde (MDA) production was seen in TTA-treated GaMg and D54Mg cells, but not in BT4Cn cells, in vitro. In BT4Cn tumor tissue from TTA-treated rats, MDA was increased while the alpha-tocopherol content tended to decrease. TTA increased the level of cytosolic cytochrome c in BT4Cn cells, which suggests induction of apoptotic cascades. Although several mechanisms are likely to be involved in the TTA-mediated effects on growth, we propose that modulation of cellular redox conditions caused by changes in fatty acid metabolism may be of vital importance.     

Perfluoro-N-decanoic acid effects on enzymes of fatty acid metabolism

In vitro perfluorodecanoate (PFDA) effects on Pseudomonas acyl-CoA synthetase, Candida acyl-CoA oxidase and pigeon muscle carnitine acetyltransferase were examined. Synthetase made little PFDA-CoA from PFDA. It used palmitate, oleate, laurate and decanoate more extensively. PFDA inhibited acyl-CoA formation from these acids. Palmitoyl-CoA formation was affected most. That of decanoyl-CoA was affected least. Inhibitions appeared to be competitive. Acyl-CoA oxidase test substrates were palmitoyl-CoA, lauroyl-CoA and decanoyl-CoA. Oxidase preferred C-10 and C-12 acyl-CoAs. PFDA inhibited oxidation of C-10 and C-12 acyl-CoAs more than that of palmitoyl-CoA. Inhibitions with C-16 and C-10 acyl-CoAs were competitive, KIs 593 +/- 150 and 76 +/- 6.0 microM. Acetyl-CoA was the best acetyltransferase substrate. C-2 to C-8 transfer from acyl-CoAs was inhibited similarly by PFDA. Inhibitions of C-2 and C-8 transfer were competitive and non-competitive, respectively, KIs 111 +/- 15 and 76 +/- 28 microM.     

Probing the skin permeation of eicosapentaenoic acid and ketoprofen 2. Comparative depth profiling and metabolism of eicosapentaenoic acid.

Unexpected enhancement of the topical delivery of eicosapentaenoic acid (EPA) across porcine skin was observed previously when fish oil was co-formulated with ketoprofen. In the current work depth profile analysis was used to probe the epidermal conversion of EPA to its 15-hydroxy metabolite in the presence and absence of ketoprofen. Freshly excised full-thickness porcine skin in Franz diffusion cells was dosed (both infinite and finite) with simple formulations based on fish oil as source of EPA. After 24h the skin was subjected to tape stripping and depth profiles were constructed. Typical depth profiles were obtained, with an inverse relationship between depth and permeant concentration. 15-HEPE was generated in the skin when Hepes-modified Hanks' balanced salt solution was used, but none was detected when a cetrimide receptor phase was used, highlighting the importance of maintaining skin viability in such exercises. Ketoprofen had a direct influence on the metabolism of EPA and resulting in conversion to its 15-LOX metabolite 15-HEPE. However, this link appears to be only part of the solution of EPA enhancement however, as even in non-viable skin ketoprofen had an enhancing affect.     

Effect of omega-3 fatty acid supplementation on the arachidonic acid:eicosapentaenoic acid ratio

STUDY OBJECTIVES: To determine the baseline arachidonic acid:eicosapentaenoic acid (AA:EPA) ratio in patients with coronary artery disease and healthy subjects, and whether supplementation of omega-3 fatty acids, administered as fish oil capsules, affects this ratio. DESIGN: Prospective, open-label trial. SETTING: University-affiliated cardiology clinic. SUBJECTS: Thirty patients with stable coronary artery disease (CAD) and 30 healthy subjects. INTERVENTION: All participants received omega-3 fatty acids 1.5 g/day for 4 weeks, followed by 3 g/day for an additional 4 weeks. MEASUREMENTS AND MAIN RESULTS: For each participant, a lipid profile was determined at baseline and after 4 weeks of treatment with each dose. Other laboratory results analyzed were serum AA:EPA ratios, high-sensitivity C-reactive protein (hs-CRP) levels, and blood glucose levels. Mean +/- SD baseline AA:EPA ratios were 39.6 +/- 19.0 in healthy subjects and 23.7 +/- 12.5 in patients with CAD. These ratios decreased significantly in both groups after treatment with 1.5 g/day of omega-3 fatty acids: 9.0 +/- 4.2 in healthy subjects and 10.3 +/- 8.8 in patients with CAD. After treatment with 3 g/day, the ratios were further reduced: 5.1 +/- 3.2 in healthy subjects and 4.9 +/- 2.6 in patients with CAD. Supplementation with omega-3 fatty acids did not significantly affect hs-CRP, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, or blood glucose levels. Triglyceride levels were not reduced in patients with CAD but were significantly decreased in healthy subjects (by 20% decrease with omega-3 fatty acids 1.5 g/day and by 32% decrease with 3 g/day). CONCLUSION: Treatment with omega-3 fatty acids significantly reduced AA:EPA ratios in both healthy subjects and in patients with stable CAD. The treatment had no effect on hs-CRP levels in either group, and it reduced triglyceride levels in healthy subjects but not in patients with CAD.     

Synergistic anti-inflammatory effects of low doses of curcumin in combination with polyunsaturated fatty acids: Docosahexaenoic acid or eicosapentaenoic acid

Inflammatory response plays an important role not only in the normal physiology but also in the pathology such as cancers. As chronic inflammations are associated with malignancies, it is important to prevent inflammation-mediated neoplastic formation, promotion and/or progression. One possible intervention will be using cancer chemopreventive agents such as curcumin (CUR), a potent anti-inflammatory and anti-oxidative stress compound. Polyunsaturated fatty acids (PUFA) such as docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) are potent anti-inflammatory agents by decreasing the production of inflammatory eicosanoids, cytokines, and reactive oxygen species (ROS). The present study aims at examining whether CUR with DHA or EPA would have synergistic anti-inflammatory effects in RAW 264.7 cells. Non-toxic concentrations of single and combination of the compounds were investigated at 6, 12 and 24 h. The nitric oxide (NO) suppression effects were most prominent at 24 h. All the combinations of CUR and DHA or EPA with lower concentrations of CUR 5 μM and 25 μM of DHA or EPA were found to have synergistic effects in suppressing LPS-stimulated NO and endogenous NO levels. Importantly, very low doses of CUR 2.5 μM and DHA or EPA of 0.78 μM could synergistically suppress the LPS-induced prostaglandin E₂ (PGE₂). The combinations were also found to suppress iNOS, COX-2, 5-lipoxygenase (5-LOX) and cPLA₂ but induce HO-1. Taken together, the present study clearly shows the synergistic anti-inflammatory as well as anti-oxidative stress effects of CUR and PUFA.     

Omega-3 fatty acid eicosapentaenoic acid. A new treatment for psychiatric and neurodegenerative diseases: a review of clinical investigations

Decreased n-3 fatty acid levels have been reported in patients with depression, schizophrenia or Alzheimer's disease. Recently, eicosapentaenoic acid (EPA) has been used to treat several psychiatric and neurodegenerative diseases due to its anti-inflammatory and neuroprotective effects. A total of six out of seven clinical trials have shown that EPA significantly improved depressive symptoms when compared with the placebo-treated populations. Several investigations have also reported that EPA could effectively treat schizophrenia. A case report and a clinical trial have shown that EPA was beneficial for the management of most symptoms of Huntington's disease, while a more extensive clinical investigation has demonstrated that EPA could only improve motor functions. Further clinical studies are required to fully explore the effects of EPA on other neurodegenerative diseases. The limitations of previous studies and further research directions have also been discussed.     

Omega-3 fatty acid eicosapentaenoic acid. A new treatment for psychiatric and neurodegenerative diseases: a review of clinical investigations

Decreased n-3 fatty acid levels have been reported in patients with depression, schizophrenia or Alzheimer's disease. Recently, eicosapentaenoic acid (EPA) has been used to treat several psychiatric and neurodegenerative diseases due to its anti-inflammatory and neuroprotective effects. A total of six out of seven clinical trials have shown that EPA significantly improved depressive symptoms when compared with the placebo-treated populations. Several investigations have also reported that EPA could effectively treat schizophrenia. A case report and a clinical trial have shown that EPA was beneficial for the management of most symptoms of Huntington's disease, while a more extensive clinical investigation has demonstrated that EPA could only improve motor functions. Further clinical studies are required to fully explore the effects of EPA on other neurodegenerative diseases. The limitations of previous studies and further research directions have also been discussed.     

Red cell and plasma fatty acid changes accompanying symptom remission in a patient with schizophrenia treated with eicosapentaenoic acid.

The administration of the omega-3 fatty acid eicosapentaenoic acid (EPA) to a drug-na?ve patient with schizophrenia, untreated with conventional antipsychotic medication, led to a dramatic and sustained clinical improvement in both positive and negative symptoms. This was accompanied by a correction in erythrocyte membranes of abnormalities in both n-3 and n-6 highly unsaturated fatty acids (HUFAs). Therefore EPA is able to reverse the phospholipid abnormalities previously described in schizophrenia. This reversal is associated with, and is likely to be the cause of, the clinical improvement. In particular, EPA appears to have reversed the depletion of not only n-3 HUFAs, but also of membrane arachidonic acid, possibly via inhibition of HUFA-specific phospholipase A(2), an enzyme which removes HUFAs from the S(N)2 position of membrane phospholipids, or by activation of a fatty acid coenzyme A ligase. Correction by EPA of abnormalities in both enzyme systems is not ruled out.     

Inhibitory effects of eicosapentaenoic acid on lipopolysaccharide-induced activation in BV2 microglia

Upon activation, microglia release proinflammatory mediators that play important roles in eliciting neuroinflammatory responses associated with neurodegenerative diseases. The anti-inflammatory properties of eicosapentaenoic acid (EPA) have been known, however, the effects responsible for lipopolysaccharide (LPS)-induced activation remain poorly understood in microglia. In the present study, we investigated the effects of EPA on the expression of proinflammatory mediators in LPS-stimulated BV2 microglia. EPA significantly inhibited the release of nitric oxide (NO), prostaglandin E(2) (PGE(2)) and proinflammatory cytokines such as interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha in a dose-dependent manner. EPA also attenuated the production of cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) and proinflammatory cytokines at mRNA and/or protein levels. Moreover, EPA suppressed NF-kappaB activation by blocking IkappaB degradation, and also blocked the mitogen-activated protein kinases (MAPKs) such as ERK, p38 and JNK, and the Akt pathway. The anti-inflammatory properties of EPA may be useful for ameliorating neurodegenerative diseases as well as suppressing LPS-induced shock.     

多不饱和脂肪酸与肝脏脂质代谢的调控

多不饱和脂肪酸(PUFA)通过调控转录因子的活性及含量调节多种基因的转录。PUFA能够激活过氧化物酶体增殖物激活受体α(PPARα),上调参与肝脏脂肪酸氧化的基因转录,抑制固醇调节元件结合蛋白-1c(SREBP-1c),下调参与肝脏脂肪合成的基因表达。PPARα与SREBP-1c在非酒精性脂肪肝(NAFLD)的发病过程中发挥重要作用。本文就PUFA对PPARα、SREBP-1c及其他参与脂质代谢的核转录因子如肝脏X受体、肝脏核因子-4等的调控加以综述,为NAFLD的治疗提供新思路。     

Effects of eicosapentaenoic acids on oxidative stress and plasma fatty acid composition in patients with lupus nephritis

Eicosapentaenoic acid (EPA) is one of the major components of fish oil, which was reported to have antiatherogenic, anti-inflammatory and immune suppressive effects. In the present study, highly purified EPA was administered to patients with lupus nephritis and the effects of EPA on urinary 8-isoprostane, a reliable marker of oxidative stress, were investigated in these patients. Six outpatients (1 man and 5 women), with lupus nephritis diagnosed by renal biopsy, were entered in the study. We administered 1800 mg EPA ethyl-ester (purity > 95%) daily and examined the urinary 8-isoprostane levels and plasma fatty acid composition before and 3 months after EPA treatment. The urinary 8-isoprostane levels were significantly decreased after the treatment compared with those before the treatment (from 530 +/- 113 pg/mg x Cr to 235 +/- 49 pg/mg x Cr, p = 0.02). The EPA levels in the plasma phospholipid (PL) fraction were significantly increased after the treatment (from 3.30 +/- 0.64 mol% to 8.01 +/- 0.47 mol%, p < 0.001). Arachidonic acid (AA) levels in the plasma PL fraction were significantly decreased after the treatment (from 9.47 +/- 0.28 mol% to 7.33 +/- 0.43 mol%, p < 0.001). The ratios of EPA to AA were significantly increased after the treatment (from 0.35 +/- 0.07 to 1.14 +/- 0.16, p < 0.001). Thus, this preliminary study indicated that EPA might exert beneficial effects on lupus nephritis by decreasing the oxidative stress.     

Food preservative sorbic acid deregulates hepatic fatty acid metabolism

Sorbic acid (SA) is one of the most commonly used food preservatives worldwide. Despite SA having no hepatotoxicity at legal dosages, its effect on hepatic lipid metabolism is still unclear. We investigated the effect of SA on hepatic lipid metabolism and its mechanism of action in C57BL/6 mice. Daily treatment with SA (1 g/kg in diet) for 4 weeks did not alter the body weight, organ weight, and blood lipids in mice. However, hepatic lipid accumulation, particularly that of triglycerides, fatty acids, and glycerol, but not cholesteryl ester and free cholesterol, was increased with SA treatment. Mechanistically, SA decreased the expression of proteins related to de novo fatty acid lipogenesis, fatty acid internalization, and very low-density lipoprotein (VLDL) secretion-related pathways, including sterol regulatory element-binding proteins, acetyl-coA carboxylase, fatty acid synthase, liver fatty acid-binding protein, CD36, and apolipoprotein E. In contrast, SA increased the expression of diacylglycerol O-acyltransferase 2, the key enzyme for triacylglycerol synthesis. Moreover, SA downregulated the protein expression of autophagy-related and β-oxidation-related pathways, the two major metabolic pathways for lipid metabolism, including LC-3, beclin-1, autophagy related protein 5 (ATG-5) and ATG-7, acyl-CoA synthetase long chain family member 1, carnitine palmitoyltransferase Iα, peroxisome proliferator-activated receptor α (PPARα), PPARγ, and PPARγ coactivator-1. Collectively, SA deregulates de novo lipogenesis and fatty acid internalization, VLDL secretion, autophagy, and β-oxidation in the liver, leading to impaired lipid clearance and ultimately, resulting in lipid accumulation in the liver.     

Protective effects of eicosapentaenoic acid on genotoxicity and oxidative stress of cyclophosphamide in mice

The aim of this article is to elucidate the mechanism by which eicosapentaenoic acid (EPA) acts against cyclophosphamide (CP)‐induced effects. The prevalence of micronuclei, the extent of lipid peroxidation, and the status of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) in both liver and serum of mice were used as intermediate biomarkers of chemoprotection. Lipid peroxidation and associated compromised antioxidant defenses (CAT and GPX) in CP treated mice were observed in the liver, serum, and were accompanied by increased prevalence of micronuclei in bone marrow. The number of MN was significantly different (p < 0.01) between the groups treated with CP (group III, IV, V, VI) and the solvent control (group II) (3.2 ± 0.7‰). There was a dose‐dependent reduction in formation CP induced micronuclei by treatment with 100, 200, or 300 mg EPA/kg BW mice. Activities of SOD, CAT, and extent of lipid peroxidation were statistically different in liver cells of mice exposed to EPA only with CP compared with the CP group (group III). The present findings imply that EPA may be a potential antigenotoxic, antioxidant and chemopreventive agent and could be used as an adjuvant in chemotherapeutic applications. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2011.     

Pharmacology and safety of tetradecylthioacetic acid (TTA): phase-1 study

This study describes the clinical, hematological, and biochemical safety of tetradecylthioacetic acid (TTA). A total of 18 healthy volunteers were included. Subjects were randomly assigned into 3 groups according to the daily given dose of TTA: group 1 (200 mg), group 2 (600 mg), and group 3 (1000 mg). TTA was given as a single oral dose for 7 consecutive days. Safety was evaluated by following the adverse events, vital signs, and hematological and biochemical parameters in blood and urine samples. Efficacy was estimated through its effects on plasma lipids profile. Few adverse events of mild severity were reported. No clinically significant changes were observed in the hematological or clinical chemical parameters in blood/urine. TTA did not induce significant changes in the blood lipids or free fatty acids, but it did result in an increase in plasma concentration of Delta9 desaturated TTA (TTA: 1n-8). Serum concentration pattern of TTA at day 1 showed a 1.5-hour lag time followed by a rapid absorption and a slower elimination phase. The median peak values were 2.9 mg/L (range, 1.1 to 5.4 mg/L), 11.5 mg/L (range, 4 to 35 mg/L), and 11 mg/L (range, 5 to 25 mg/L), in groups 1, 2, and 3, respectively (P = 0.006). The time to peak levels were 3.5 hours (range, 2.5 to 6.5 hours), 2.5 hours (range, 2.5 to 4.5 hours), and 4.5 hours (range, 2.5 to 12 hours), respectively (P = 0.2). TTA is safe and well tolerated.     

Comparative bioavailability of eicosapentaenoic acid and docasahexaenoic acid from triglycerides, free fatty acids and ethyl esters in volunteers

Comparative Bioavailability of Eicosapentaenoic Acid and Docosahexaenoic Acid from Triglycerides, Free Fatty Acids and Ethyl Esters in Volunteers. The bioavailability of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from triglycerides, free fatty acids and ethyl esters was investigated in 8 female volunteers in a randomized triple cross-over trial with baseline control. EPA/DHA was administered in capsules in form of triglycerides (1.68/0.72 g), free fatty acids (1.35/1.065 g) and ethyl esters (1.86/1.27 g). The resulting EPA/DHA plasma levels were determined and evaluated. The mean relative bioavailability of EPA/DHA compared to triglycerides was 186/136% from free fatty acids and 40/48% from ethyl esters. Maximal plasma levels were about 50% higher with free fatty acids and about 50% lower with ethyl esters as compared to triglycerides. The tolerability of the free fatty acids was much worse than that of triglycerides and ethyl esters. The main side effect was eructation.     

Immunomodulatory effects of eicosapentaenoic acid through induction of regulatory T cells

Dietary intake of omega-3 polyunsaturated fatty acids (PUFAs) has been found to affect inflammation and metabolism, and many researchers have shown that omega-3 PUFAs provide benefits in immunologic and metabolic disorders. These effects were assumed to result mainly from a modification in the production of inflammatory mediators and the suppression of inflammatory leukocytes. Among PUFAs, eicosapentaenoic acid (EPA), a component of fish oil, apparently has the most potent effect. Recently, much research has focused on regulatory T cells (Tregs) as controllers of immune responses not only to self-antigens but also to non-self-antigens, including donor alloantigens. Therefore, induction of antigen-specific Tregs may be an attractive strategy for managing autoimmune diseases and transplant rejection. Peroxisome proliferator-activated receptor γ (PPARγ), a ligand-activated nuclear receptor that regulates lipid and glucose metabolism, can be activated by thiazolidinediones, fatty acids, and eicosanoids, including EPA. PPARγ was recently found to have immunoregulatory effects, and a PPARγ agonist inhibited immune responses in a rat model of autoimmune disease. Furthermore, in a murine model, one high dose of purified EPA given the day of transplantation induced marked prolongation of cardiac allograft survival in a dose-dependent manner. These findings suggest that EPA induced Tregs by means of a PPARγ-dependent mechanism. This review describes the immunomodulatory effects of PUFAs, especially EPA, and summarizes recent research that may have implications for the development of therapies for autoimmune diseases and transplant rejection that are based on induction of Tregs.     

In vitro effects of Etodolac and acetylsalicylic acid on human chondrocyte metabolism.

The effects of two nonsteroidal anti-inflammatory drugs (NSAIDs), Etodolac (ETO) and acetylsalicylic acid (ASA), used at pharmacological concentrations, were tested on several metabolic parameters of human chondrocytes cultivated in three-dimensional culture. The results indicated that proteoglycan synthesis was significantly decreased by ASA treatment, whereas Etodolac did not affect this parameter. Neither ASA nor Etodolac modified type-II collagen production. Both NSAIDs were potent inhibitors of PGE2 production, but Etodolac was more efficient at equimolar concentrations. In contrast, collagenolytic activity was unaffected by Etodolac.     

调节胆汁酸代谢及肠道菌群对非酒精性脂肪肝治疗效果研究

目的通过动物实验研究探讨调节饮食-胆汁酸-肠道菌群治疗非酒精性脂肪性肝病(NAFLD)的疗效。方法随机选择小鼠40只,分四组,每组10只,Ⅰ组采用普通饲料;Ⅱ组采用高脂饲料;Ⅲ组普通饲料,并给予头孢曲松钠。Ⅳ组高脂饲料,同时应用头孢曲松钠。喂养12周,采血化验甘油三酯(TG)、胆固醇(TC)、丙氨酸氨基转移酶(ALT)、谷氨酰氨基转移酶(AST)、胆汁酸(TBA)、脂联素、粪便胆汁酸水平,行肠道菌群培养比较,并测定肝匀浆组织血脂成分。根据Ⅳ组方式喂养小鼠32只,12周后均停用抗生素,给予普通饮食、无菌水,将其随机平均分为四组,每组8只,A组为对照组;B组给予熊去氧胆酸;C组给予枯草杆菌二联活菌;D组给予熊去氧胆酸及枯草杆菌二联活菌。ABCD四组小鼠均饲养12周后再次检测上述指标进行比较。结果Ⅱ、Ⅳ组小鼠,TG、ALT、AST、TBA、粪便胆汁酸水平均明显升高,差异有统计学意义(P 0.01)。Ⅲ组ALT、AST水平明显升高,差异有统计学意义(P 0.01)。B组ALT、AST、TBA,C组TG、ALT、AST、脂联素,D组TG、ALT、AST、TBA与A组比较,差异有统计学意义(P 0.05)。B、C、D组粪便胆汁酸水平较A组有明显变化,有统计学意义。各组与对照组比较肝匀浆血脂成分差异有统计学意义(P 0.05)。Ⅲ、Ⅳ组肠道菌群失调明显,双歧杆菌、乳酸杆菌、肠杆菌下降明显,肠球菌水平升高,差异有统计学意义(P 0.01)。C、D组肠道菌群改善明显,差异有统计学意义(P 0.01)。结论肠道菌群、胆汁酸代谢与NAFLD发生发展相关,通过调节肠道菌群及胆汁酸水平可以改善肝脏脂质代谢及肝功能,促进肝脏恢复。