Randomized Trial of Zileuton for Treatment of COPD Exacerbations Requiring Hospitalization

Rationale: Leukotrienes have been implicated in the pathogenesis of acute exacerbations of COPD, but leukotriene modifiers have not been studied as a possible therapy for exacerbations. Objective: We sought to test the safety and efficacy of adding oral zileuton (a 5-lipoxygenase inhibitor) to usual treatment for acute exacerbations of COPD requiring hospitalization. Methods: Randomized double-blind, placebo-controlled, parallel group study of zileuton 600 mg orally, 4 times daily versus placebo for 14 days starting within 12 hours of hospital admission for COPD exacerbation. Primary outcome measure was hospital length of stay; secondary outcomes included treatment failure and biomarkers of leukotriene production. Main Findings: Sixty subjects were randomized to zileuton and 59 to placebo (the study was stopped short of enrollment goals because of slow recruitment). There was no difference in hospital length of stay (3.75 ± 2.19 vs. 3.86 ± 3.06 days for zileuton vs. placebo, p = 0.39) or treatment failure (23% vs. 27% for zileuton vs. placebo, p = 0.63) despite a decline in urinary LTE₄ levels in the zileuton-treated group as compared to placebo at 24 hours (change in natural log-transformed ng/mg creatinine ?1.38 ± 1.19 vs. 0.14 ± 1.51, p < 0.0001) and 72 hours (?1.32 ± 2.08 vs. 0.26 ± 1.93, p<0.006). Adverse events were similar in both groups. Principal Conclusions: While oral zileuton during COPD exacerbations that require hospital admission is safe and reduces urinary LTE₄ levels, we found no evidence suggesting that this intervention shortened hospital stay, with the limitation that our sample size may have been insufficient to detect a modest but potentially meaningful clinical improvement.     

局灶性脑缺血再灌注致血脑屏障破坏与zileuton的保护作用

目的： 探讨局灶性脑缺血再灌注损伤（CIRI）致血脑屏障(BBB) 通透性破坏的影响因素,观察高选择性5-脂氧合酶（5-LO）抑制剂zileuton的保护作用并分析其机制。方法: 线栓法制备大鼠大脑中动脉闭塞2 h/再灌注24 h模型（MCAO2 h/R24 h）,于缺血前2 h、再灌注0、5、10 h,分别灌胃给予zileuton10、50 mg·kg-1。伊文氏蓝示踪剂检测BBB;AutoCAD图像分析软件计算脑水肿程度;RT-PCR法检测脑组织白三烯受体1mRNA（CysLTR1 mRNA）;ELISA法检测血清白三烯B4（LTB4）;免疫组化法检测脑组织水通道蛋白4（AQP4）、基质金属蛋白酶9（MMP-9）蛋白。结果: MCAO2 h/R24 h后,BBB通透性明显增高,出现脑水肿,血清LTB4含量升高,梗塞侧脑组织CysLTR1mRNA表达增强,缺血区与梗塞灶周边缺血半暗带（IP）区AQP4与MMP-9蛋白表达上调; zileuton10、50 mg·kg-1均能有效控制CIRI所致的BBB破坏,改善脑水肿,降低血清LTB4含量,下调脑组织CysLTR1mRNA、AQP4与MMP-9表达。结论: CIRI后BBB通透性明显破坏,zileuton的保护作用与抑制脑组织和循环血液中的5-LO通路活化、下调脑组织缺血区与IP区的AQP4与MMP-9蛋白表达有关。     

Zileuton对局灶性脑缺血/再灌注致急性肺损伤的保护作用

目的探讨选择性5-脂氧合酶(5-LO)抑制剂zileu-ton对局灶性脑缺血/再灌注损伤(CIRI)引发急性肺损伤(ALI)的保护作用及其机制。方法线栓法制作大鼠大脑中动脉闭塞/再灌注(MCAO/R)模型,缺血2h,再灌注24h。于缺血前2h,再灌注0、5、10h,分别4次灌胃给予zileuton 10、50mg·kg-1。HE染色观察肺组织形态学改变;湿干重比(W/D)检测肺组织含水量;RT-PCR法检测肺组织白三烯受体1 mRNA(CysLTR1 mRNA);酶联免疫吸附法(ELISA)检测血清白三烯B4(LTB4)浓度;免疫组化法检测肺组织肿瘤坏死因子-α(TNF-α)蛋白;生化法检测肺组织髓过氧化物酶(MPO)、总抗氧化能力(T-AOC)和Na+,K+-ATPase活性。结果Zileuton10、50mg·kg-1均可改善肺组织病理变化,减少肺组织W/D比值(P<0.01),并下调肺组织CysL-TR1mRNA和TNF-α蛋白表达(P<0.05,P<0.01),降低血清LTB4浓度(P<0.01),缓解肺组织MPO升高和Na+,K+-ATPase活性下降(P<0.05,P<0.01),提高肺组织T-AOC(P<0.05,P<0.01)。结论Zileuton可有效抑制CIRI所致的ALI,其机制与抑制5-LO通路活性,减轻肺组织炎症反应、氧化损伤和离子转运障碍有关。     

Zileuton prevents the activation of the leukotriene pathway and reduces sebaceous lipogenesis

Please cite this paper as: Zileuton prevents the activation of the leukotriene pathway and reduces sebaceous lipogenesis. Experimental Dermatology 2010; 19: 148–150. Abstract: Arachidonic acid (AA) activates the 5‐lipoxygenase, induces leukotriene‐B₄ (LTB₄) synthesis, enhances interleukin‐6 (IL‐6) release and increases intracellular neutral lipids in human sebocytes. Moreover, the enzymes of LTB₄ biosynthesis are activated in acne‐involved sebaceous glands. Zileuton a 5‐lipoxygenase inhibitor, reduces the number of inflammatory acne lesions and lipogenesis in patients with acne. In this study, we investigated the activity of zileuton on LTB₄ generation, lipid content and IL‐6 and ‐8 release from human SZ95 sebocytes in vitro. Pretreatment with zileuton partially prevented the AA‐induced LTB₄ and IL‐6 release and increased neutral lipid content. IL‐6 release and neutral lipid content were also reduced under long‐term zileuton treatment. In conclusion, zileuton prevents the activation of the leukotriene pathway and enhancement of lipogenesis by AA in human sebocytes in vitro.     

5-脂氧合酶抑制剂齐留通对胰腺癌细胞SW1990的生长抑制作用

目的观察5-脂氧合酶(5-LOX)在胰腺癌细胞SW1990中蛋白、mRNA水平的表达,探讨5-LOX特异性抑制剂齐留通对胰腺癌细胞SW1990增殖和凋亡的影响及可能机制。方法2003-05-10—2004-05-25,南通大学附属医院消化实验室采用半定量反转录-聚和酶链反应(RT-PCR)法和免疫细胞化学方法检测5-LOX在胰腺癌细胞SW1990中的表达,采用四甲基偶氮唑盐(MTT)法和流式细胞仪检测齐留通对细胞的生长抑制作用。结果胰腺癌细胞SW1990中5-LOXmRNA及蛋白表达阳性,齐留通明显抑制胰腺癌细胞生长,并呈时间、浓度依赖性。结论5-LOX特异性抑制剂齐留通对胰腺癌细胞有显著的生长抑制作用,为胰腺癌的防治提供了一个新的实验依据。     

齐留通对胰腺癌细胞增殖与凋亡的影响

[摘要]目的 探讨齐留通阻断5-脂氧合酶（5-LOX）代谢途径对胰腺癌细胞增殖和凋亡的影响。方法 将胰腺癌细胞SW1990与不同浓度齐留通（浓度分别为40，30，20，10，5，3和1 μg·mL-1）共同孵育,以不加齐留通的细胞为对照组。采用MTT法检测作用不同时间后齐留通对SW1990细胞的抑制率；倒置显微镜观察齐留通浓度为20 μg·mL-1时细胞形态变化；将SW1990胰腺癌细胞与不同浓度齐留通（浓度分别为80，40，20，10和5 μg·mL-1）作用24 h，对照组加入等量培养基和溶媒，流式细胞仪(FCM)AnnexinⅤ/PI双染法检测各组SW1990细胞增殖指数， FCM检测细胞周期。结果 培养48 h后，40和30 μg·mL-1齐留通组对胰腺癌SW1990细胞增殖的抑制作用明显强于对照组，且均差异有极显著性（均P<0.01）；培养72 h后，40，30和20 μg·mL-1齐留通组对胰腺癌细胞的抑制较对照组显著增强（均P<0.01）。其他检测结果亦表明，齐留通可抑制SW1990细胞增殖，促进细胞凋亡，该作用呈浓度和时间依赖性。与对照组相比, 20 μg·mL-1齐留通作用18 h后G0/G1期细胞所占比例较对照组明显增高（P<0.01）,G2/M期、S期细胞所占比例降低。结论 齐留通能抑制胰腺癌细胞增殖并诱导细胞凋亡，使细胞DNA合成受抑制,产生G1期阻滞。     

A rat air pouch model for evaluating the efficacy and selectivity of 5-lipoxygenase inhibitors

The 5-lipoxygenase (5-LOX) pathway has been associated with a variety of inflammatory diseases including asthma, atherosclerosis, rheumatoid arthritis, pain, cancer and liver fibrosis. Several classes of 5-LOX inhibitors have been identified, but only one drug, zileuton, a redox inhibitor of 5-LOX, has been approved for clinical use. To better evaluate the efficacy of 5-LOX inhibitors for pharmacological intervention, a rat model was modified to test the in vivo efficacy of 5-LOX inhibitors. Inflammation was produced by adding carrageenan into a newly formed air pouch and prostaglandins produced. While macrophages and neutrophils are present in the inflamed pouch, little 5-LOX products are formed. Cellular 5-LOX activation was obtained by adding calcium ionophore (A23187) into the pouch thus providing a novel model to evaluate the efficacy and selectivity of 5-LOX inhibitors. Also, we described modifications to the in vitro 5-LOX enzyme and cell assays. These assays included a newly developed fluorescence-based enzyme assay, a 5-LOX redox assay, an ex vivo human whole blood assay and an IgE-stimulated rat mast cell assay, all designed for maximal production of leukotrienes. Zileuton and CJ-13,610, a competitive, non-redox inhibitor of 5-LOX, were evaluated for their pharmacological properties using these assays. Although both compounds achieved dose-dependent inhibition of 5-LOX enzyme activity, CJ-13,610 was 3-4 fold more potent than zileuton in all-assays. Evaluation of 5-LOX metabolites-by LC/MS/MS and ELISA confirmed that both compounds selectively inhibited all products downstream of 5-hydroperoxy eicosatetraenoic acid (5-HPETE), including 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxoETE), without inhibition of 12-lipoxygenase (12-LOX), 15-lipoxygenase (15-LOX), or cyclooxygenase (COX) products. In the rat air pouch model, oral dosing of CJ-13,610 and zileuton resulted in selective inhibition 5-LOX activity from pouch exudate and ex vivo rat whole blood with similar potency to in vitro assay. These data show that the rat air pouch model is a reliable and useful tool for evaluating in vivo efficacy of 5-LOX inhibitors and may aid in the development of the next generation of 5-LOX inhibitors, such as the non-redox inhibitors similar to CJ-13,610.     

The effect of 5-lipoxygenase inhibition on Ascaris antigen (Ag)-induced responses in atopic monkeys

The effects of two 5-lipoxygenase (5LO) inhibitors, ZD2138 or Zileuton, on acute, inflammatory responses to aerosolizedAscaris suum (Ag) were determined in atopicMacaca fascicularis monkeys. Monkeys (n=6 each group) were dosed with vehicle, 3 or 10 mg/kg ZD2138, or 30 mg/kg Zileuton (p.o.). Both ZD2138 or Zileuton significantly inhibited ex vivo LTB₄ production in Ca²⁺ ionophore-stimulated whole blood from these same monkeys (n=6 each group) by 45.5% (3 mg/kg ZD2138), 82.5% (10 mg/kg ZD2138) and 84.3% (30 mg/kg Zileuton). ZD2138 (10 mg/kg) reduced bronchoalveolar lavage (BAL) LTE₄ levels (65.1% inhibition), BAL neutrophils (88.9% inhibition), and IL-6 (54.0% inhibition) 4h post Ag. Zileuton inhibited these responses and also reduced BAL levels of IL-8 (73.4% inhibition). A second study was performed to evaluate the effects of ZD2138 on chronic Ag-induced responses. Treatment with ZD2138 did not prevent pulmonary inflammation or the development of airway hyperresponsiveness (AHR). Based upon these results, 5LO inhibition significantly reduced ex vivo LTB₄ and in vivo LTE₄ production as well as several acute inflammatory responses to Ag in the lung. However, ZD2138 did not inhibit more chronic responses following multiple Ag exposure.accepted by M.J. Parnham     

Development and Validation of a Liquid Chromatography-Mass Spectrometry Method for the Determination of Zileuton in Human Plasma

A selective and sensitive liquid chromatography-tandem mass spectrometric method (LC-MS/MS) has been developed and validated for the quantification of zileuton in human plasma. Deuterated internal standard (zileuton D4) was used as the internal standard (ISTD). Zileuton was extracted by liquid-liquid extraction using methyl tert-butyl ether and separated by isocratic elution on a C18 column (100 × 4.6 mm, 5 μm, Discovery C18) with the mobile phase consisting of 1 mM ammonium acetate buffer and methanol in the ratio of 10:90. A flow rate of 1.0 ml/min was used with isocratic elution. Multiple reaction monitoring transitions in positive mode for zileuton and the internal standard were 237.3/161.2 and 241.2/161.1, respectively. The method was validated within the linearity range of 50.5–10,012.7 ng/ml for the bioanalytical method validation parameters like selectivity, accuracy, precision, recovery, stability, and matrix effect.     

5-脂氧合酶抑制剂齐留通对胰腺癌细胞SW1990的生长抑制作用

目的 观察5-脂氧合酶（5-LOX）在胰腺癌细胞SW1990中蛋白、mRNA水平的表达，探讨5-LOX特异性抑制剂齐留通对胰腺癌细胞SW1990增殖和凋亡的影响及可能机制。方法2003—05—10-2004—05—25，南通大学附属医院消化实验室采用半定量反转录-聚和酶链反应（RT—PCR）法和免疫细胞化学方法检测5-LOX在胰腺癌细胞SW1990中的表达，采用四甲基偶氮唑盐（M1Tr）法和流式细胞仪检测齐留通对细胞的生长抑制作用。结果胰腺癌细胞SW1990中5-LOXmRNA及蛋白表达阳性，齐留通明显抑制胰腺癌细胞生长，并呈时间、浓度依赖性。结论 5-LOX特异性抑制剂齐留通对胰腺癌细胞有显著的生长抑制作用，为胰腺癌的防治提供了一个新的实验依据。