leukotriene-d4 and Ischemia

The anti-inflammatory effects of pranlukast, an antagonist of cysteinyl leukotriene receptor 1, may be rendered not only by antileukotriene activity but also by other pharmacological activities. Previous studies indicate that pranlukast reduces ischemic tissue injury partially through decreasing vascular permeability, but its effect on ischemic injury in endothelial cells is not known. Thus, in this study, we investigated the effect of pranlukast on ischemia-like injury induced by oxygen-glucose deprivation (OGD) in EA.hy926 cells, a human endothelial cell line, and the possible mechanisms. We found that cell viability was reduced, lactate dehydrogenase release was increased 4-8 hours after OGD, and necrosis was induced 8 hours after OGD. Production of reactive oxygen species (ROS) increased by 211%, 176%, and 128%, respectively, 0.5, 1, and 2 hours after OGD. Nuclear factor-kappaB (NF-kappaB) was translocated to the nuclei 4-8 hours after OGD. Pranlukast ameliorated the reduced viability, the increased lactate dehydrogenase release, and necrosis after OGD. It also reduced ROS production and inhibited NF-kappaB nuclear translocation after OGD. The ROS scavenger, edaravone, inhibited OGD-induced nuclear translocation of NF-kappaB as well. Edaravone and pyrrolidine dithiocarbamate (a specific NF-kappaB inhibitor) protected endothelial cells from the OGD-induced injury. However, zileuton, a 5-lipoxygenase inhibitor, did not affect the cell injury, ROS production, and NF-kappaB nuclear translocation after OGD. The exogenous leukotriene D4 did not induce cell injury, ROS production, and NF-kappaB translocation. Thus, we conclude that pranlukast protects endothelial cells from ischemia-like injury via decreasing ROS production and inhibiting NF-kappaB activation, which is leukotriene independent.

Topics: Arachidonate 5-Lipoxygenase; Cell Line; Cell Nucleus; Cell Survival; Chromones; Endothelial Cells; Glucose; Humans; Ischemia; Leukotriene Antagonists; Leukotriene D4; Leukotrienes; Necrosis; NF-kappa B; Oxygen; Reactive Oxygen Species

Endotoxinaemia stimulates the generation of cysteinyl leukotrienes (LT), potent mediators of inflammation which are preferentially eliminated into the bile. Nitric oxide (NO) is a mediator molecule that has a possible protective role in liver injury. As sepsis and shock often lead to the development of hypoxic regions in the liver, the influence of hypoxia on the metabolism of cysteinyl leukotrienes and the hepatic production of NO were investigated in the isolated perfused rat liver. Livers were perfused in a non-recirculating haemoglobin-free system from the portal to the caval vein. Perfusion medium was equilibrated with 95% O2/5% CO2. In hypoxia experiments, gassing was changed to 95% N2/5% CO2 for 20 min. Tritiated leukotrienes were infused to the portal vein and metabolites in effluent and bile were measured by HPLC. Hypoxia did not influence the uptake of 3H-LTC4 and 3H-LTE4 but biliary elimination was reduced by 50-60% compared to normoxic control experiments. In hypoxia, the metabolite pattern in bile was also significantly changed with a decrease of omega-oxidation products. Following reoxygenation larger amounts of leukotrienes were excreted from the liver into the bile. To induce NO synthase in the liver, rats were injected intraperitoneally with endotoxin 6 hours before livers were isolated for perfusion. In contrast to nontreated livers, nitrite and nitrate, the oxidation products of NO, were detectable in the effluent perfusate. Basal NO2(-)+NO3- release was 5.3 (1.2) nmol/g liver/min. NO2(-)+NO3- release was stimulated by L-arginine infusion, whereas hypoxia resulted in an almost complete inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Amino Acid Oxidoreductases; Animals; Bile; Cell Hypoxia; Ischemia; Leukotriene C4; Leukotriene D4; Leukotrienes; Liver; Male; Nitric Oxide; Nitric Oxide Synthase; Perfusion; Rats; Rats, Wistar; Shock, Septic