Conjugated linoleic acid increases intracellular ROS synthesis and oxygenation of arachidonic acid in macrophages.
OBJECTIVE
Conjugated linoleic acids (CLAs) have potential antiatherosclerotic properties: they may inhibit atherosclerotic processes by reducing the intensity of inflammatory processes. However, in vivo studies have shown that the application of trans-10, cis-12 CLA in obese men increased their oxidative stress. The objective of this study was to determine whether CLA can lead to an increase in oxidative stress and to isoprostane synthesis in macrophages.


METHODS
Monocytes from peripheral blood and human monocytic leukemia cells were used in this study. Monocytes were differentiated to macrophages, and were incubated with 30 microM cis-9, trans-11 CLA and trans-10, cis-12 CLA or linoleic acid for 2 days. In some experiments the inhibitors of peroxisome proliferator-activated receptor-alpha (PPAR-alpha) or respiratory chain were added. After incubation, synthesis of reactive oxygen species (ROS), total cellular concentration of adenosine triphosphate, concentration of 8-epi-prostaglandin F2 alpha, activity of cytoplasolic phospholipase A2 (cPLA2), activity of mitochondria, and expression of mRNA of PPAR-alpha were measured.


RESULTS
In cells cultured with CLAs intercellular ROS synthesis increased. In this condition the mitochondrial energy potential was high, and the inhibitors of the respiratory chain and PPAR-alpha reduced ROS concentration. At the same time, the cPLA2 activity was abolished. In contrast, 8-iPF2 alpha III synthesis increased in CLA cells.


CONCLUSIONS
Cultivation of cells with CLA leads to an increased ROS synthesis, partly by PPAR-alpha mechanism. An increase in ROS concentration and inhibition of cPLA2 activity can stimulate oxygenation of arachidonic acid and contribute to an increase in 8-epi-PF2 alpha III level and in the apoptosis process in macrophages.
Stachowska
Ewa
E
Laboratory of Biochemistry and Medical Chemistry, Pomeranian Medical University, Szczecin, Poland. ewa.stachowska@akuna.pl <ewa.stachowska@akuna.pl>
Baśkiewicz-Masiuk
Magdalena
M
Dziedziejko
Violetta
V
Gutowska
Izabela
I
Baranowska-Bosiacka
Irena
I
Marchlewicz
Mariola
M
Dołegowska
Barbara
B
Wiszniewska
Barbara
B
Machaliński
Bogusław
B
Chlubek
Dariusz
D
D017209:Apoptosis / Q000187:drug effects; D016718:Arachidonic Acid / Q000378:metabolism*; D015153:Blotting, Western; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000096:biosynthesis; D006801:Humans; D007536:Isomerism; D028421:Isoprostanes / Q000378:metabolism; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology*; D008264:Macrophages / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D047493:PPAR alpha / Q000378:metabolism; D010741:Phospholipases A / Q000378:metabolism; D016133:Polymerase Chain Reaction; D017382:Reactive Oxygen Species / Q000378:metabolism*
D018076:DNA, Complementary; D028421:Isoprostanes; D044243:Linoleic Acids, Conjugated; D047493:PPAR alpha; D017382:Reactive Oxygen Species; D016718:Arachidonic Acid; D010741:Phospholipases A