14,15-EET involved in the development of diabetic cardiac hypertrophy mediated by PPARs.

Cardiac hypertrophy is a key structural change in diabetic cardiomyopathy, which mechanism is unknown. 14,15-Epoxyeicosatrienoic acid (14,15-EET) generated from arachidonic acid by CYP2J2 has beneficial effects in metabolic syndrome, which also plays vital roles in inflammatory response. Peroxisome proliferator activated receptors (PPARs) are members of the nuclear receptor superfamily and have three subtypes of α, ß (or δ) and γ. Studies have found that 14,15-EET can perform various biological functions by activating PPARs, but its role in diabetic cardiac hypertrophy is unknown. This study aimed to investigate the role of 14,15-EET-PPARs signaling pathway in the development of diabetic cardiac hypertrophy. Diabetic cardiac hypertrophy was developed by high-fat diet feeding combined with streptozotocin (40 mg/kg/d for 5 days, i.p.) in mice and was induced by glucose at 25.5 mmol/L (high glucose, HG) in H9c2 cells. The decreased level of 14,15-EET and the down-regulated expression of PPARα, PPARß and PPARγ were found following diabetic cardiac hypertrophy in mice. Similarly, both the level of 14,15-EET and the PPARs expression were also reduced in HG-induced hypertrophic cardiomyocytes. Supplementation with 14,15-EET improved the cardiomyocyte hypertrophy and up-regulated PPARs expression, which were nullified by 14,15-EEZE, a 14,15-EET antagonist. Taken together, we conclude that the decreased 14,15-EET is involved in the development of diabetic cardiac hypertrophy through the down-regulation of PPARs.

11,12 Epoxyeicosatrienoic Acid Rescues Deteriorated Wound Healing in Diabetes.

Epoxyeicosatrienoic acids (EET) facilitate regeneration in different tissues, and their benefit in dermal wound healing has been proven under normal conditions. In this study, we investigated the effect of 11,12 EET on dermal wound healing in diabetes. We induced diabetes by i.p. injection of streptozotocin 2 weeks prior to wound creation on the dorsal side of the mouse ear. 11,12 EET was applied every second day on the wound, whereas the control groups received only solvent. Epithelialization was monitored every second day intravitally up to wound closure. Wounds were stained for VEGF, CD31, TGF-ß, TNF-α, SDF-1α, NF-κB, and Ki-67, and fibroblasts were counted after hematoxylin-eosin stain on days 3, 6, 9, and 16 after wounding. After induction of diabetes, wounds closed on day 13.00 ± 2.20 standard deviation (SD). Local 11,12 ETT application improved wound closure significantly to day 8.40 ± 1.39 SD. EET treatment enhanced VEGF and CD31 expression in wounds on day 3. It also seemed to raise TNF-α level on all days investigated as well as TGF-ß level on days 3 and 6. A decrease in NF-κB could be observed on days 9 and 16 after EET application. The latter findings were not significant. SDF-1α expression was not influenced by EET application, and Ki-67 was significantly less in the EET group on day 9 after EET application. The number of fibroblasts was significantly increased on day 9 after the 11,12 EET application. 11,12 EET improve deteriorated wound healing in diabetes by enhancing neoangiogenesis, especially in the early phase of wound healing. Furthermore, they contribute to the dissolution of the initial inflammatory reaction, allowing the crucial transition from the inflammatory to proliferative phase in wound healing.

Essential Fatty Acid Requirements and Intravenous Lipid Emulsions.

Linoleic acid (LA) and α-linolenic acid (ALA) must be supplied to the human body and are therefore considered essential fatty acids. This narrative review discusses the signs, symptoms, diagnosis, prevention, and treatment of essential fatty acid deficiency (EFAD). EFAD may occur in patients with conditions that severely limit the intake, digestion, absorption, and/or metabolism of fat. EFAD may be prevented in patients requiring parenteral nutrition by inclusion of an intravenous lipid emulsion (ILE) as a source of LA and ALA. Early ILEs consisted solely of soybean oil (SO), a good source of LA and ALA, but being rich in LA may promote the production of proinflammatory fatty acids. Subsequent ILE formulations replaced part of the SO with other fat sources to decrease the amount of proinflammatory fatty acids. Although rare, EFAD is diagnosed by an elevated triene:tetraene (T:T) ratio, which reflects increased metabolism of oleic acid to Mead acid in the absence of adequate LA and ALA. Assays for measuring fatty acids have improved over the years, and therefore it is necessary to take into account the particular assay used and its reference range when determining if the T:T ratio indicates EFAD. In patients with a high degree of suspicion for EFAD, obtaining a fatty acid profile may provide additional useful information for making a diagnosis of EFAD. In patients receiving an ILE, the T:T ratio and fatty acid profile should be interpreted in light of the fatty acid composition of the ILE to ensure accurate diagnosis of EFAD.

Intravenous Fish Oil and Serum Fatty Acid Profiles in Pediatric Patients With Intestinal Failure-Associated Liver Disease.

BACKGROUND: Intravenous fish oil (FO) treats pediatric intestinal failure-associated liver disease (IFALD). There are concerns that a lipid emulsion composed of ω-3 fatty acids will cause an essential fatty acid deficiency (EFAD). This study's objective was to quantify the risk for abnormal fatty acid concentrations in children treated with FO. METHODS: Inclusion criteria for this prospective study were children with intestinal failure. Intravenous soybean oil (SO) was replaced with FO for no longer than 6 months. Serum fatty acids were analyzed using linear and logistic models, and compared with age-based norms to determine the percentage of subjects with low and high concentrations. RESULTS: Subjects (n = 17) started receiving FO at a median of 3.6 months (interquartile range 2.4-9.6 months). Over time, α-linolenic, linoleic, arachidonic, and Mead acid decreased, whereas docosahexaenoic and eicosapentaenoic acid increased (P < 0.001 for all). Triene-tetraene ratios remained unchanged (P = 1). Although subjects were 1.8 times more likely to develop a low linoleic acid while receiving FO vs SO (95% CI: 1.4-2.3, P < 0.01), there was not a significant risk for low arachidonic acid. Subjects were 1.6 times more likely to develop high docosahexaenoic acid while receiving FO vs SO; however, this was not significant (95% CI: 0.9-2.6, P = 0.08). CONCLUSION: In this cohort of parenteral nutrition-dependent children, switching from SO to FO led to a decrease in essential fatty acid concentrations, but an EFAD was not evident. Low and high levels of fatty acids developed. Further investigation is needed to clarify if this is clinically significant.

Alleviation of Mechanical Allodynia by 14,15-Epoxyeicosatrienoic Acid in a Central Poststroke Pain Model: Possible Role of Allopregnanolone and δ-Subunit-Containing Gamma-Aminobutyric Acid A Receptors.

Central poststroke pain (CPSP) is a neuropathic pain syndrome arising after a lesion of the central nervous system owing to cerebrovascular insult. Impaired daily activities and reduced quality of life in people suffering from CPSP justify the need for improved treatment. The detailed mechanism of CPSP is not well understood, but central disinhibition has been suggested. Recent reports indicated that epoxyeicosatrienoic acids (EETs), the cytochrome P450 metabolites of arachidonic acid, promoted neuronal survival after stroke, displayed antinociception in peripheral inflammatory pain, and reduced neuronal excitability in seizure model. Here, we tested the hypothesis that 14,15-EET may attenuate CPSP by suppressing thalamic disinhibition through neurosteroids-δ-subunit-containing gamma-aminobutyric acid A receptors (δGABAAR) signaling. In this study, we used a rat model of thalamic hemorrhagic stroke to induce CPSP. Pain behavioral tests revealed that CPSP rats exhibited mechanical allodynia, starting at day 7 postlesion and lasting at least 4 weeks. Analysis of the perithalamic lesion tissue from the brain of CPSP rats demonstrated a decrease of 14,15-EET content, steroidogenic acute regulatory protein expression, and allopregnanolone (AP) production. This was accompanied by reduced δGABAAR expression in the medial thalamus at 4 weeks postlesion. Intrathalamic injection of exogenous 14,15-EET into the ventral posterior lateral nucleus attenuated mechanical allodynia, induced a marked increase in the abundance of the steroidogenic acute regulatory protein and AP along the lesion site and a concomitant increase in δGABAAR expression in the medial thalamus under CPSP condition. However, this antinociceptive effect could be eliminated by the 5α-reductase inhibitor finasteride or dutasteride or GABAAR antagonist bicuculline. Moreover, compared with the current first-line drug gabapentin for central neuropathic pain, an early treatment of EET showed greater efficacy in the secondary prevention of CPSP. Taken together, this study provided a proof of concept that EETs may have anti-CPSP effect by reserving normal thalamic inhibition through AP-δGABAAR signaling. PERSPECTIVE: Agents targeting EETs may serve as potential therapeutic options for stroke, the use of which at the initial period could not only block further nerve damage but also prevent the occurrence of CPSP.

Dronedarone-Induced Cardiac Mitochondrial Dysfunction and Its Mitigation by Epoxyeicosatrienoic Acids.

Dronedarone and amiodarone are structurally similar antiarrhythmic drugs. Dronedarone worsens cardiac adverse effects with unknown causes while amiodarone has no cardiac adversity. Dronedarone induces preclinical mitochondrial toxicity in rat liver and exhibits clinical hepatotoxicity. Here, we further investigated the relative potential of the antiarrhythmic drugs in causing mitochondrial injury in cardiomyocytes. Differentiated rat H9c2 cardiomyocytes were treated with dronedarone, amiodarone, and their respective metabolites namely N-desbutyldronedarone (NDBD) and N-desethylamiodarone (NDEA). Intracellular ATP content, mitochondrial membrane potential (Δψm), and inhibition of carnitine palmitoyltransferase I (CPT1) activity and arachidonic acid (AA) metabolism were measured in H9c2 cells. Inhibition of electron transport chain (ETC) activities and uncoupling of ETC were further studied in isolated rat heart mitochondria. Dronedarone, amiodarone, NDBD and NDEA decreased intracellular ATP content significantly (IC50 = 0.49, 1.84, 1.07, and 0.63 µM, respectively) and dissipated Δψm potently (IC50 = 0.5, 2.94, 12.8, and 7.38 µM, respectively). Dronedarone, NDBD, and NDEA weakly inhibited CPT1 activity while amiodarone (IC50 > 100 µM) yielded negligible inhibition. Only dronedarone inhibited AA metabolism to its regioisomeric epoxyeicosatrienoic acids (EETs) consistently and potently. NADH-supplemented ETC activity was inhibited by dronedarone, amiodarone, NDBD and NDEA (IC50 = 3.07, 5.24, 11.94, and 16.16 µM, respectively). Cytotoxicity, ATP decrease and Δψm disruption were ameliorated via exogenous pre-treatment of H9c2 cells with 11, 12-EET and 14, 15-EET. Our study confirmed that dronedarone causes mitochondrial injury in cardiomyocytes by perturbing Δψm, inhibiting mitochondrial complex I, uncoupling ETC and dysregulating AA-EET metabolism. We postulate that cardiac mitochondrial injury is one potential contributing factor to dronedarone-induced cardiac failure exacerbation.

Anti- Versus Pro-Inflammatory Metabololipidome Upon Cupping Treatment.

BACKGROUND/AIMS: This study aimed to explore the metabololipidome in mice upon cupping treatment. METHODS: A nude mouse model mimicking the cupping treatment in humans was established by administrating four cupping sets on the back skin for 15 minutes. UPLC-MS/ MS was performed to determine the PUFA metabolome in mice skin and blood before and after cupping treatment. The significantly changed lipids were administered in macrophages to assess the production of pro-inflammatory cytokines IL-6 and TNF-α by ELISA. RESULTS: The anti-inflammatory lipids, e.g. PGE1, 5,6-EET, 14,15-EET, 10S,17S-DiHDoHE, 17R-RvD1, RvD5 and 14S-HDoHE were significantly increased while pro-inflammatory lipids, e.g. 12-HETE and TXB2 were deceased in the skin or plasma post cupping treatment. Cupping treatment reversed the LPS-stimulated IL-6 and TNF-α expression in mouse peritoneal exudates. Moreover, 5,6-EET, PGE1 decreased the level of TNF-α, while 5,6-EET, 5,6-DHET downregulated IL-6 production in macrophages. Importantly, 14,15-EET and 14S-HDoHE inhibited both IL-6 and TNF-α induced by lipopolysaccharide (LPS). 17-RvD1, RvD5 and PGE1 significantly reduced the LPS-initiated TNF-α, while TXB2 and 12-HETE further upregulated the LPS-enhanced IL-6 and TNF-α expression in macrophages. CONCLUSION: Our results reveal the identities of anti-inflammatory versus pro-inflammatory metabolipidome and suggest the potential therapeutic mechanism of cupping treatment.

Intraileal casein infusion increases plasma concentrations of amino acids in humans: A randomized cross over trial.

BACKGROUND: Activation of the ileal brake by casein induces satiety signals and reduces energy intake. However, adverse effects of intraileal casein administration have not been studied before. These adverse effects may include impaired amino acid digestion, absorption and immune activation. OBJECTIVE: To investigate the effects of intraileal infusion of native casein on plasma amino acid appearance, immune activation and gastrointestinal (GI) symptoms. DESIGN: A randomized single-blind cross over study was performed in 13 healthy subjects (6 male; mean age 26 ± 2.9 years; mean body mass index 22.8 ± 0.4 kg/m-2), who were intubated with a naso-ileal feeding catheter. Thirty minutes after intake of a standardized breakfast, participants received an ileal infusion, containing either control (C) consisting of saline, a low-dose (17.2 kcal) casein (LP) or a high-dose (51.7 kcal) of casein (HP) over a period of 90 min. Blood samples were collected for analysis of amino acids (AAs), C-reactive protein (CRP), pro-inflammatory cytokines and oxylipins at regular intervals. Furthermore, GI symptom questionnaires were collected before, during and after ileal infusion. RESULTS: None of the subjects reported any GI symptoms before, during or after ileal infusion of C, LP and HP. Plasma concentrations of all AAs analyzed were significantly increased after infusion of HP as compared to C (p < 0.001), and most AAs were increased after infusion of LP (p < 0.001). In total, 12.49 ± 1.73 and 3.18 ± 0.87 g AAs were found in plasma after intraileal infusion of HP and LP, corresponding to 93 ± 13% (HP) and 72 ± 20% (LP) of AAs infused as casein, respectively. Ileal casein infusion did not affect plasma concentrations of CRP, IL-6, IL-8, IL-1ß and TNF-α. Infusion of HP resulted in a decreased concentration of 11,12-dihydroxyeicosatrienoic acid whereas none of the other oxylipins analyzed were affected. CONCLUSIONS: A single intraileal infusion of native casein results in a concentration and time dependent increase of AAs in plasma, suggesting an effective digestion and absorption of AAs present in casein. Also, ileal infusion did not result in immune activation nor in GI symptoms. CLINICALTRIALS.GOV: NCT01509469.

Functional screening for G protein-coupled receptor targets of 14,15-epoxyeicosatrienoic acid.

Epoxyeicosatrienoic acids (EETs) are potent vasodilators that play important roles in cardiovascular physiology and disease, yet the molecular mechanisms underlying the biological actions of EETs are not fully understood. Multiple lines of evidence suggest that the actions of EETs are in part mediated via G protein-coupled receptor (GPCR) signaling, but the identity of such a receptor has remained elusive. We sought to identify 14,15-EET-responsive GPCRs. A set of 105 clones were expressed in Xenopus oocyte and screened for their ability to activate cAMP-dependent chloride current. Several receptors responded to micromolar concentrations of 14,15-EET, with the top five being prostaglandin receptor subtypes (PTGER2, PTGER4, PTGFR, PTGDR, PTGER3IV). Overall, our results indicate that multiple low-affinity 14,15-EET GPCRs are capable of increasing cAMP levels following 14,15-EET stimulation, highlighting the potential for cross-talk between prostanoid and other ecosanoid GPCRs. Our data also indicate that none of the 105 GPCRs screened met our criteria for a high-affinity receptor for 14,15-EET.

12(S)-HETrE, a 12-Lipoxygenase Oxylipin of Dihomo-γ-Linolenic Acid, Inhibits Thrombosis via Gαs Signaling in Platelets.

OBJECTIVE: Dietary supplementation with polyunsaturated fatty acids has been widely used for primary and secondary prevention of cardiovascular disease in individuals at risk; however, the cardioprotective benefits of polyunsaturated fatty acids remain controversial because of lack of mechanistic and in vivo evidence. We present direct evidence that an omega-6 polyunsaturated fatty acid, dihomo-γ-linolenic acid (DGLA), exhibits in vivo cardioprotection through 12-lipoxygenase (12-LOX) oxidation of DGLA to its reduced oxidized lipid form, 12(S)-hydroxy-8Z,10E,14Z-eicosatrienoic acid (12(S)-HETrE), inhibiting platelet activation and thrombosis. APPROACH AND RESULTS: DGLA inhibited ex vivo platelet aggregation and Rap1 activation in wild-type mice, but not in mice lacking 12-LOX expression (12-LOX(-/-)). Similarly, wild-type mice treated with DGLA were able to reduce thrombus growth (platelet and fibrin accumulation) after laser-induced injury of the arteriole of the cremaster muscle, but not 12-LOX(-/-) mice, supporting a 12-LOX requirement for mediating the inhibitory effects of DGLA on platelet-mediated thrombus formation. Platelet activation and thrombus formation were also suppressed when directly treated with 12(S)-HETrE. Importantly, 2 hemostatic models, tail bleeding and arteriole rupture of the cremaster muscle, showed no alteration in hemostasis after 12(S)-HETrE treatment. Finally, the mechanism for 12(S)-HETrE protection was shown to be mediated via a Gαs-linked G-protein-coupled receptor pathway in human platelets. CONCLUSIONS: This study provides the direct evidence that an omega-6 polyunsaturated fatty acid, DGLA, inhibits injury-induced thrombosis through its 12-LOX oxylipin, 12(S)-HETrE, which strongly supports the potential cardioprotective benefits of DGLA supplementation through its regulation of platelet function. Furthermore, this is the first evidence of a 12-LOX oxylipin regulating platelet function in a Gs α subunit-linked G-protein-coupled receptor-dependent manner.

Inhibition of epoxyeicosatrienoic acid production in rats with cirrhosis has beneficial effects on portal hypertension by reducing splanchnic vasodilation.

UNLABELLED: In cirrhosis, 11,12-epoxyeicosatrienoic acid (EET) induces mesenteric arterial vasodilation, which contributes to the onset of portal hypertension. We evaluated the hemodynamic effects of in vivo inhibition of EET production in experimental cirrhosis. Sixteen control rats and 16 rats with carbon tetrachloride-induced cirrhosis were studied. Eight controls and eight rats with cirrhosis were treated with the specific epoxygenase inhibitor N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH; 20 mg/kg/day) for 3 consecutive days. Portal blood flow and renal and splenic resistive indexes were calculated through echographic measurements, while portal and systemic pressures were measured through polyethylene-50 catheters. Small resistance mesenteric arteries were connected to a pressure servo controller in a video-monitored perfusion system, and concentration-response curves to phenylephrine and acetylcholine were evaluated. EET levels were measured in tissue homogenates of rat liver, kidney, and aorta, using an enzyme-linked immunosorbent assay. Urinary Na(+) excretion function was also evaluated. In rats with cirrhosis, treatment with MS-PPOH significantly reduced portal blood flow and portal pressure compared to vehicle (13.6 ± 5.7 versus 25.3 ± 7.1 mL/min/100 g body weight, P < 0.05; 9.6 ± 1.1 versus 12.2 ± 2.3 mm Hg, P < 0.05; respectively) without effects on systemic pressure. An increased response to acetylcholine of mesenteric arteries from rats with cirrhosis (50% effect concentration -7.083 ± 0.197 versus -6.517 ± 0.73 in control rats, P < 0.05) was reversed after inhibition of EET production (-6.388 ± 0.263, P < 0.05). In liver, kidney, and aorta from animals with cirrhosis, treatment with MS-PPOH reversed the increase in EET levels. In both controls and rats with cirrhosis, MS-PPOH increased urinary Na(+) excretion. CONCLUSION: In rats with cirrhosis, in vivo inhibition of EET production normalizes the response of mesenteric arteries to vasodilators, with beneficial effects on portal hypertension. (Hepatology 2016;64:923-930).

Cardiotonic Pill Reduces Myocardial Ischemia-Reperfusion Injury via Increasing EET Concentrations in Rats.

Accumulating data suggest that epoxyeicosatrienoic acids (EETs) and 20-hydroxyeicosatetraenoic acid, both cytochrome P450 (P450) enzyme metabolites of arachidonic acid (AA), play important roles in cardiovascular diseases. For many years, the cardiotonic pill (CP), an herbal preparation derived from Salviae Miltiorrhizae Radix et Rhizoma, Notoginseng Radix et Rhizoma, and Borneolum Syntheticum, has been widely used in China for the treatment of coronary artery disease. However, its pharmacological mechanism has not been well elucidated. The purpose of this study was to investigate the chronic effects of the CP on myocardial ischemia-reperfusion injury (MIRI) and AA P450 enzyme metabolism in rats (in vivo) and H9c2 cells (in vitro). The results showed that CP dose dependently (10, 20, and 40 mg/kg/d; 7 days) mitigated MIRI in rats. The plasma concentrations of EETs in CP-treated ischemia-reperfusion (I/R) rats (40 mg/kg/d; 7 days) were significantly higher (P < 0.05) than those in controls. Cardiac Cyp1b1, Cyp2b1, Cyp2e1, Cyp2j3, and Cyp4f6 were significantly induced (P < 0.05); CYP2J and CYP2C11 proteins were upregulated (P < 0.05); and AA-epoxygenases activity was significantly increased (P < 0.05) after CP (40 mg/kg/d; 7 days) administration in rats. In H9c2 cells, the CP also increased (P < 0.05) the EET concentrations and showed protection in hypoxia-reoxygenation (H/R) cells. However, an antagonist of EETs, 14,15-epoxyeicosa-5(Z)-enoic acid, displayed a dose-dependent depression of the CP's protective effects in H/R cells. In conclusion, upregulation of cardiac epoxygenases after multiple doses of the CP-leading to elevated concentrations of cardioprotective EETs after myocardial I/R-may be the underlying mechanism, at least in part, for the CP's cardioprotective effect in rats.

Essential Fatty Acid Deficiency in 2015: The Impact of Novel Intravenous Lipid Emulsions.

The fatty acids, linoleic acid (18:2ω-6) and α-linolenic acid (18:3ω-3), are essential to the human diet. When these essential fatty acids are not provided in sufficient quantities, essential fatty acid deficiency (EFAD) develops. This can be suggested clinically by abnormal liver function tests or biochemically by an elevated Mead acid and reduced linoleic acid and arachidonic acid level, which is manifested as an elevated triene/tetraene ratio of Mead acid/arachidonic acid. Clinical features of EFAD may present later. With the introduction of novel intravenous (IV) lipid emulsions in North America, the proportion of fatty acids provided, particularly the essential fatty acids, varies substantially. We describe a case series of 3 complicated obese patients who were administered parenteral nutrition (PN), primarily using ClinOleic 20%, an olive oil-based lipid emulsion with reduced amounts of the essential fatty acids, linoleic and α-linolenic, compared with more conventional soybean oil emulsions throughout their hospital admission. Essential fatty acid profiles were obtained for each of these patients to investigate EFAD as a potential cause of abnormal liver enzymes. Although the profiles revealed reduced linoleic acid and elevated Mead acid levels, this was not indicative of the development of essential fatty acid deficiency, as reflected in the more definitive measure of triene/tetraene ratio. Instead, although the serum fatty acid panel reflected the markedly lower but still adequate dietary linoleic acid content and greatly increased oleic acid content in the parenteral lipid emulsion, the triene/tetraene ratio remained well below the level, indicating EFAD in each of these patients. The availability and use of new IV lipid emulsions in PN should encourage the clinician to review lipid metabolism based on the quantity of fatty acids provided in specific parenteral lipid emulsions and the expected impact of these lipid emulsions (with quite different fatty acid composition) on measured fatty acid profiles.

Inhibition of soluble epoxide hydrolase does not improve the course of congestive heart failure and the development of renal dysfunction in rats with volume overload induced by aorto-caval fistula.

The detailed mechanisms determining the course of congestive heart failure (CHF) and associated renal dysfunction remain unclear. In a volume overload model of CHF induced by creation of aorto-caval fistula (ACF) in Hannover Sprague-Dawley (HanSD) rats we explored the putative pathogenetic contribution of epoxyeicosatrienoic acids (EETs), active products of CYP-450 dependent epoxygenase pathway of arachidonic acid metabolism, and compared it with the role of the renin-angiotensin system (RAS). Chronic treatment with cis-4-[4-(3-adamantan-1-yl-ureido) cyclohexyloxy]benzoic acid (c-AUCB, 3 mg/l in drinking water), an inhibitor of soluble epoxide hydrolase (sEH) which normally degrades EETs, increased intrarenal and myocardial EETs to levels observed in sham-operated HanSD rats, but did not improve the survival or renal function impairment. In contrast, chronic angiotensin-converting enzyme inhibition (ACEi, trandolapril, 6 mg/l in drinking water) increased renal blood flow, fractional sodium excretion and markedly improved survival, without affecting left ventricular structure and performance. Hence, renal dysfunction rather than cardiac remodeling determines long-term mortality in advanced stage of CHF due to volume overload. Strong protective actions of ACEi were associated with suppression of the vasoconstrictor/sodium retaining axis and activation of vasodilatory/natriuretic axis of the renin-angiotensin system in the circulating blood and kidney tissue.

Mead acid (20:3n-9) and n-3 polyunsaturated fatty acids are not associated with risk of posterior longitudinal ligament ossification: results of a case-control study.

Ossification of the posterior longitudinal ligament (OPLL) involves the replacement of ligamentous tissue with ectopic bone. Although genetics and heritability appear to be involved in the development of OPLL, its pathogenesis remains to be elucidated. Given previous findings that 5,8,11-eicosatrienoic acid [20:3n-9, Mead acid (MA)] has depressive effects on osteoblastic activity and anti-angiogenic effects, and that n-3 polyunsaturated fatty acids (PUFAs) have a preventive effect on heterotopic ossification, we hypothesized that both fatty acids would be involved in OPLL development. To examine the biological significance of these and other fatty acids in OPLL, we conducted this case-control study involving 106 patients with cervical OPLL and 109 age matched controls. Fatty acid composition was determined from plasma samples by gas chromatography. Associations between fatty acid levels and incident OPLL were evaluated by logistic regression. Contrary to our expectations, we found no significant differences between patients and controls in the levels of MA or n-3 PUFAs (e.g., eicosapentaenoic acid and docosahexaenoic acid). Logistic regression analysis did not reveal any associations with OPLL risk for MA or n-3 PUFAs. In conclusion, no potential role was found for MA or n-3 PUFAs in ectopic bone formation in the spinal canal.

Hyperbaric oxygenation modulates vascular reactivity to angiotensin-(1-7) in diabetic rats: potential role of epoxyeicosatrienoic acids.

Previously, a facilitating effect of hyperbaric oxygenation (HBO2) on aortic ring responses to angiotensin-(1-7) in healthy rats was reported, with epoxyeicosatrienoic acids (EETs) possibly playing an important role. The aim of this study was to assess whether HBO2 exerts similar effects in diabetic rats and to further explore the role of specific cytochrome P450 (CYP) enzymes in changes induced by HBO2. Aortic relaxation to angiotensin-(1-7) was significantly higher in HBO2 diabetic rats compared to control diabetic rats, while HBO2 had no effect on angiotensin II contraction. N-methylsulphonyl-6-(2-propargyloxyphenyl/hexanamide inhibited the facilitation of angiotensin-(1-7) responses in HBO2 rats, suggesting an important role of EETs in this modulation. mRNA expression of CYP2J3 and protein expression of CYP2C11 were significantly upregulated in HBO2 diabetic rats, whereas CYP4A1, CYP4A2 and CYP4A3 mRNA and CYP2J3 protein expression was similar between groups. Mean arterial pressure, ferric reducing ability of plasma and Thiobarbituric Acid Reactive Substances levels and serum angiotensin-(1-7) concentrations were not significantly changed.

Whatever happened to the epoxyeicosatrienoic Acid-like endothelium-derived hyperpolarizing factor? The identification of novel classes of lipid mediators and their role in vascular homeostasis.

SIGNIFICANCE: Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acid (AA) to generate epoxyeicosatrienoic acids (EETs). The latter are biologically active and reported to act as an endothelium-derived hyperpolarizing factor as well as to affect angiogenic and inflammatory signaling pathways. RECENT ADVANCES: In addition to AA, the CYP enzymes also metabolize the ω-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid and docosahexaenoic acid to generate bioactive lipid epoxide mediators. The latter can be more potent than the EETs, but their actions are under investigated. The ω3-epoxides, like the EETs, are metabolized by the soluble epoxide hydrolase (sEH) to corresponding diols, and epoxide hydrolase inhibition increases epoxide levels and demonstrates anti-hypertensive as well as anti-inflammatory effects. CRITICAL ISSUES: It seems that the overall consequences of CYP activation largely depend on enzyme substrate preference and the endogenous ω-3/ω-6 PUFA ratio. FUTURE DIRECTIONS: More studies combining PUFA profiling with cell signaling and disease studies are required to determine the spectrum of molecular pathways affected by the different ω-6 and ω-3 PUFA epoxides and diols. Such information may help improve dietary studies aimed at promoting health via ω-3 PUFA supplementation and/or sEH inhibition.

The α-tocopherol form of vitamin E reverses age-associated susceptibility to streptococcus pneumoniae lung infection by modulating pulmonary neutrophil recruitment.

Streptococcus pneumoniae infections are an important cause of morbidity and mortality in older patients. Uncontrolled neutrophil-driven pulmonary inflammation exacerbates this disease. To test whether the α-tocopherol (α-Toc) form of vitamin E, a regulator of immunity, can modulate neutrophil responses as a preventive strategy to mitigate the age-associated decline in resistance to S. pneumoniae, young (4 mo) and old (22-24 mo) C57BL/6 mice were fed a diet containing 30-PPM (control) or 500-PPM (supplemented) α-Toc for 4 wk and intratracheally infected with S. pneumoniae. Aged mice fed a control diet were exquisitely more susceptible to S. pneumoniae than young mice. At 2 d postinfection, aged mice suffered 1000-fold higher pulmonary bacterial burden, 2.2-fold higher levels of neutrophil recruitment to the lung, and a 2.25-fold higher rate of lethal septicemia. Strikingly, α-Toc supplementation of aged mice resulted in a 1000-fold lower bacterial lung burden and full control of infection. This α-Toc-induced resistance to pneumococcal challenge was associated with a 2-fold fewer pulmonary neutrophils, a level comparable to S. pneumoniae-challenged, conventionally fed young mice. α-Toc directly inhibited neutrophil egress across epithelial cell monolayers in vitro in response to pneumococci or hepoxilin-A3, an eicosanoid required for pneumococcus-elicited neutrophil trans-epithelial migration. α-Toc altered expression of multiple epithelial and neutrophil adhesion molecules involved in migration, including CD55, CD47, CD18/CD11b, and ICAM-1. These findings suggest that α-Toc enhances resistance of aged mice to bacterial pneumonia by modulating the innate immune response, a finding that has potential clinical significance in combating infection in aged individuals through nutritional intervention.

Food allergy in small children carries a risk of essential fatty acid deficiency, as detected by elevated serum mead acid proportion of total fatty acids.

BACKGROUND: Elevated serum Mead acid as a proportion of total fatty acids is an indirect marker of a deficiency of essential fatty acids (EFA). The aim of the study was to evaluate the symptoms and nutrition of food-allergic children with elevated or normal serum Mead acid. METHODS: Serum fatty acid compositions from 400 children were studied by clinical indications, mostly by suspicion of deficiency of EFA due to inadequate nutrition. A Mead acid level exceeding 0.21% (percentage of total fatty acids) was considered to be a specific sign of an insufficient EFA supply. From a total of 31 children with elevated Mead acid (MEADplus group), 23 (74%) had food allergy. The symptoms and dietary restrictions of this MEADplus group of food allergic children were compared to 54 age-and sex-matched controls with food allergy but normal Mead acid proportions (MEADminus group) before and 6 months after the serum fatty acid determination. RESULTS: At the beginning of the 6-month follow-up, 44% of the food allergic children in both MEADplus and MEADminus groups were on an elimination diet. These diets did not differ between the two groups and we were not able to document an association between the severity of elimination diet and elevated Mead acid proportion. However, the MEADplus children were on average more symptomatic than MEADminus children. In the MEADplus group, food allergy presented with skin symptoms in 100% (vs. 70% in the MEADminus group, p < 0.001) and with vomiting or diarrhea in 70% (vs. 44% in the MEADminus group, p < 0.05). Clinical suspicion of malnutrition resulted in increase in the use of vegetable oil and milk-free margarine in both groups from <50% to 65-74% during the follow-up. After 6 months, 64% of the MEADplus children with food allergy had been sent to a control serum fatty acid analysis. Of these children, Mead acid had declined to normal level in 69%, and remained elevated in 31%. CONCLUSIONS: Severe symptoms of food allergy combined with elimination diets in children may lead to insufficient nutrition presenting with elevated serum Mead acid. Adding of supplementary polyunsaturated fat to the diet should be considered in these children.

Systemic disease during Streptococcus pneumoniae acute lung infection requires 12-lipoxygenase-dependent inflammation.

Acute pulmonary infection by Streptococcus pneumoniae is characterized by high bacterial numbers in the lung, a robust alveolar influx of polymorphonuclear cells (PMNs), and a risk of systemic spread of the bacterium. We investigated host mediators of S. pneumoniae-induced PMN migration and the role of inflammation in septicemia following pneumococcal lung infection. Hepoxilin A3 (HXA3) is a PMN chemoattractant and a metabolite of the 12-lipoxygenase (12-LOX) pathway. We observed that S. pneumoniae infection induced the production of 12-LOX in cultured pulmonary epithelium and in the lungs of infected mice. Inhibition of the 12-LOX pathway prevented pathogen-induced PMN transepithelial migration in vitro and dramatically reduced lung inflammation upon high-dose pulmonary challenge with S. pneumoniae in vivo, thus implicating HXA3 in pneumococcus-induced pulmonary inflammation. PMN basolateral-to-apical transmigration in vitro significantly increased apical-to-basolateral transepithelial migration of bacteria. Mice suppressed in the expression of 12-LOX exhibited little or no bacteremia and survived an otherwise lethal pulmonary challenge. Our data suggest that pneumococcal pulmonary inflammation is required for high-level bacteremia and systemic infection, partly by disrupting lung epithelium through 12-LOX-dependent HXA3 production and subsequent PMN transepithelial migration.