13-HODE inhibits the intracellular calcium increase of activated human polymorphonuclear cells

We studied the effect of the linoleic acid metabolite 13-hydroxyoctadecadienoic acid (13-HODE) on the increase of the intracellular calcium concentration, [Ca2+]i, induced by platelet-activating factor (PAF), leukotriene B4 (LTB4), and formyl-Met-Leu-Phe (fMLP) in human polymorphonuclear leukocytes (PMNs). 13-HODE by itself did not change the [Ca2+]i of PMNs. However, when PMNs were preincubated with 13-HODE and subsequently stimulated with PAF, LTB4, or fMLP, an inhibition of the increase of the [Ca2+]i was observed. The PAF-induced calcium response was concentration-dependently inhibited between 0.1 and 5 microM 13-HODE. These results suggest that 13-HODE can affect the increase of the [Ca2+]i and hence can modulate activation of PMNs.