Differential production of prostaglandins and prostacyclins by liver and head kidney cells from Atlantic salmon challenged with arachidonic and eicosapentaenoic acids.

Polyunsaturated fatty acids such as arachidonic and eicosapentaenoic acids are the precursors of eicosanoid metabolites (e.g prostaglandins and prostacyclins) which regulate inflammatory and immune response processes in fish organs. The present research studies the differential production of PGI2, PGI3, PGE2 and PGE3 by primary liver and head kidney cells isolated from salmon and challenged with single or combined ARA and/or EPA. There was a significant increase in the production of PGE2 and PGI3 in both types of cells after exposure to single and combined fatty acids. Increased production of PGE3 was only detected in liver cells after exposure to ARA+EPA. The levels of PGI2 in liver cells were significantly increased after exposure to all the tested fatty acid systems, while the production levels in head kidney cells were only significant after exposure to ARA or ARA+EPA, but not to EPA, where the production was non-significantly decreased compared to the control cells. In general, liver cells synthetized higher prostaglandin levels than prostacyclins, and the opposite was observed in head kidney cells, which synthetized highly remarkable amounts of prostacyclin compared to liver cells. The overall production for both types of cells and various fatty acid systems were characterized by a high proportion of the omega-3 fatty acid metabolites (PGE3+PGI3) compared to the omega-6 counterpart (PGE2+PGI2). Some potential production mechanisms are proposed and comprehensively discussed. The results of the present research are the first to deliver the differential production of prostacyclins and prostaglandins by liver and head kidney cells from salmon, thereby paving the way for understanding the significance of these prostanoids in fish physiology and disease.

The Effect of Omega-3 and Omega-6 Polyunsaturated Fatty Acids on the Production of Cyclooxygenase and Lipoxygenase Metabolites by Human Umbilical Vein Endothelial Cells.

Although the correlation between polyunsaturated fatty acids (PUFA) and the production of pro- and anti-inflammatory metabolites is well documented, little is known about the simultaneous effect of different PUFA on the production of cyclooxygenase and lipoxygenase metabolites. The present research examines the association between different omega-3 (ω-3) and omega-6 (ω-6) PUFA and the release of four cyclooxygenase and six lipoxygenase metabolites in cell medium by human umbilical vein endothelial cells (HUVEC). The different combinations of ω-3 and ω-6 PUFA were prepared according to a full 24 factorial design that enables studying not only the main effects but also the different interactions between fatty acids. In addition, interactions diagrams and principal component analysis were useful tools for interpreting higher order interactions. To the best of our knowledge, this is the first report addressing the combined effect of ω-3 and ω-6 PUFA on the signaling of prostaglandins, prostacyclins, leukotrienes and resolvins by HUVEC.

Hypotensive and bradycardic effects of quinovic acid glycosides from Aspidosperma fendleri in spontaneously hypertensive rats.

The Aspidosperma genus (Apocynaceae) represents one of the largest sources of indole alkaloids widely associated with cardiovascular effects. Aspidosperma fendleri, a plant found mainly in Venezuela, has a single phytochemical report in which is revealed the presence of alkaloids in its seeds. This study explored the cardiovascular effects of an ethanolic extract of A. fendleri leaves (EEAF) in spontaneously hypertensive rats (SHR) and its potential bioactive compounds. Using bioguided fractionation, fractions and pure compounds were intravenously administered to SHR and their effects on mean arterial blood pressure (MABP) and heart rate (HR) monitored over time. EEAF induced hypotensive and bradycardic effects as shown by significant reductions in mean arterial blood pressure (MABP) and heart rate (HR), respectively. Bioactivity-guided fractionation led to the isolation of a mixture of two known isomeric triterpenoid glycosides identified by spectral evidence as quinovic acid 3-O-ß-rhamnopyranoside and quinovic acid 3-O-ß-fucopyranoside. This mixture of triterpenoid saponins induced reductions in MABP and HR similar to those induced by propranolol. Together, these findings indicate that the two quinovic acid glycosides are responsible for the hypotensive and bradycardic effects which suggest their potential use in cardiovascular therapy.

Chemical constituents from Licania cruegeriana and their cardiovascular and antiplatelet effects.

Three new lupane-type triterpenoids: 6ß,30-dihydroxybetulinic acid glucopyranosyl ester (4), 6ß,30-dihydroxybetulinic acid (5) and 6ß-hydroxybetulinic acid (6), were isolated from Licania cruegeriana Urb. along with six known compounds. Their structures were elucidated on the basis of spectroscopic methods, including IR, ESIMS, 1D- and 2D-NMR experiments, as well as by comparison of their spectral data with those of related compounds. All compounds were evaluated in vivo for their effects on the mean arterial blood pressure (MABP) and heart rate (HR) of spontaneously hypertensive rats (SHR) and also in vitro for their capacity to inhibit the human platelet aggregation. None of the isolated flavonoids 1-3 showed cardiovascular effects on SHR and among the isolated triterpenoids 4-9 only 5 and 6 produced a significant reduction in MABP (60.1% and 17.2%, respectively) and an elevation in HR (11.0% and 41.2%, respectively). Compounds 3, 4, 5 and 6 were able to inhibit human platelet aggregation induced by ADP, collagen and arachidonic acid with different selectivity profiles.

The impact of exogenous ω-6 and ω-3 polyunsaturated fatty acids on the induced production of pro- and anti-inflammatory prostaglandins and leukotrienes in Atlantic salmon head kidney cells using a full factorial design and LC-MS/MS.

The production of prostaglandins (PGE2, PGE3) and leukotrienes (LTB4, LTB5) in salmon head kidney cell cultures, exposed to different combinations of 20:4ω-6, 20:5ω-3 and 22:6ω-3 polyunsaturated fatty acids (PUFAs), was evaluated by means of a two level factorial design and LC-MS/MS. The method was selective for the pro- and anti-inflammatory analytes and their corresponding stable-isotope labelled internal standards. The regression models were linear over the concentration range 0.5-150 ng/ml with limits of detection of 0.25 ng/ml and quantification of 0.40 ng/ml for the analysed metabolites. The recovery ranged from 78 to 107% for prostaglandins and 73 to 115% for leukotrienes. The analysis of the samples exposed to different combinations of PUFAs revealed that the presence of single ω-3 PUFAs brought an enhancement of the metabolites from the lipooxygenase pathway, specially LTB4, and a reduction of the metabolites from the cyclooxygenase pathway (PGE2 and PGE3), while the two-term interactions generated the opposite effect (high concentration of prostaglandins and low concentrations of leukotrienes). To our knowledge, this is the first implementation of a fully crossed design for investigating the impact of ω-6 and ω-3 PUFAs on the production of eicosanoids not only through their individual but also through their combined effects on Atlantic salmon head kidney cells.

Development and validation of an extraction method for the determination of pro-inflammatory eicosanoids in human plasma using liquid chromatography-tandem mass spectrometry.

A simple method coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated for the extraction of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) from human plasma. The extraction protocol consisted of adding formic acid (10 µL) and acetonitrile (140 µL) to human plasma (50 µL) and further injection of the supernatant (25 µL) into the LC-MS/MS. The method was selective for PGE2 and LTB4 and the regression models, based on deuterated internal standards (30 ng mL(-1) PGE2-d4 and 40 ng mL(-1) LTB4-d4), were linear over the concentration range 1.0-50.0 ng mL(-1) with limits of detection (3 × σblank) and quantification (6 × σblank) of 0.5 ng mL(-1) and 1 ng mL(-1) for both eicosanoids. The recovery ranges were 95.1-104.7% for PGE2 and 86.4-103.2% for LTB4. The developed method was successfully implemented on plasma samples from patients before and after exposure to certain anti-inflammatory treatment.