过氧化氢对原代培养大鼠肝细胞的毒性作用及其机理

本文报道了过氧化氢诱发原代培养大鼠肝细胞毒性作用的可能机理．过氧化氢（０．２～１．０ｍｍｏｌ·Ｌ－１）温育６ｈ可以引起大鼠肝细胞坏死性损伤，导致谷丙转氨酶释放增加及细胞存活率下降，加入过氧化氢酶（２５０～１５００Ｕ·ｍＬ－１）及抗氧化剂五味子乙素（１０～１００μｍｏｌ·Ｌ－１）均可降低过氧化氢的毒性作用．加入过氧化氢（０．６和１．０ｍｍｏｌ·Ｌ－１）可在６ｍｉｎ内使大鼠肝细胞内钙从１８０ｎｍｏｌ·Ｌ－１明显持续升高至７００ｎｍｏｌ·Ｌ－１以上（约３．５倍）．过氧化氢与肝细胞作用３０ｍｉｎ至１ｈ既可导致细胞膜脂质过氧化，表现为丙二醛蓄积及膜流动性下降，明显早于肝细胞发生坏死性损伤的时间．肝细胞胞浆中还原型谷胱甘肽（ＧＳＨ）含量在加入过氧化氢３０ｍｉｎ后明显降低，可推测肝细胞在后面的温育中对过氧化氢毒性的敏感性增加．以上结果证实过氧化氢诱发的原代培养大鼠肝细胞致死性损伤可能与细胞内钙迅速持续增高，细胞膜脂质过氧化及ＧＳＨ含量下降有关．     

酮康唑对原代培养大鼠肝细胞的毒性作用及其机制

目的观察酮康唑（ketoconazole，KCZ）对原代培养大鼠肝细胞的毒性效应，探讨其可能的毒性机制。方法采用胶原酶二步灌流法分离制备雄性SD大鼠肝细胞，进行原代培养。量效关系研究中KCZ设56、75、94、113和188μmol／L，染毒时间4h；时效关系研究中KCZ设188μmol／L，染毒时间分别为0．5、1、2和4h；同时设溶剂对照。检测染毒后肝细胞活力、胞内LDH泄漏情况以及巯基状态的变化。结果（1）量效关系研究中，随着KCZ剂量的升高，肝细胞活力逐渐下降，培养液中LDH活力逐渐增高，肝细胞内巯基也呈下降趋势，上述指标均有明确的剂量．反应关系（γLDH=0．906，P〈0．01）；（2）时效关系研究中，KCZ在188μmol／L剂量下染毒后肝细胞活力呈时间依赖性下降；培养液中LDH活力随染毒时间延长逐渐增高；细胞内巯基出现相应性下降。结论KCZ可以导致肝细胞活力下降，胞内LDH泄漏，巯基含量减少，并有明确的量效和时效关系，提示酮康唑对肝细胞的毒作用可能与细胞内巯基状态改变有关。     

非毒性结节性甲状腺肿蛋白质表达差异的初步研究

目的：比较非毒性结节性甲状腺（NTNG）组织和正常甲状腺组织整体蛋白质表达,以研究非毒性结节性甲状腺组织蛋白质表达差异。方法提取NTNG甲状腺组织和正常甲状腺组织总蛋白,利用双向凝胶电泳技术分离各组总蛋白;经MALDI- TOF / TOF质谱分析,搜索数据库,寻找匹配的相关蛋白质,鉴定蛋白质,获得差异蛋白质的信息。结果经过初步筛选和质谱分析共获得9个具有统计学意义的表达差异蛋白点,其中4个在非毒性结节性甲状腺高表达,5个低表达。结论 NTNG与正常腺体组织间存在多种差异表达的蛋白质,可能通过细胞外基质、细胞因子、受体信号转细胞信号传递等参与NTNG的发生和发展。     

齐多夫定对原代大鼠肝细胞毒性作用的研究

目的: 研究齐多夫定对原代大鼠肝细胞的毒性.方法:采用二步灌流法分离Wistar大鼠肝细胞,经台盼蓝拒染试验测定细胞活力,活力＞85%用于实验.实验分4组:药物组、阳性对照组、阴性对照组和空白对照组.肝细胞悬液(3×105个/ml)接种于各培养板:96孔板每孔200 μl,24孔板每孔1 ml,6孔板每孔2.5 ml,各板置37℃、5%二氧化碳培养箱培养4 h,弃上清液.药物组分别加入齐多夫定10、5、3.3、2、0.4、0.08mmol/L,阳性对照组分别加入四氯化碳10、2、0.5 mmol/L,阴性对照组加入含1%二甲基亚砜(DMSO)的DMEM培养液,空白对照组加入DMEM培养液.96孔板于加样后6、12、24 h进行MTT试验测定细胞活性,24孔板于加样后6、12 h测定肝细胞AST、ALT及LDH的释放量,6孔板加样后12 h将细胞苏木素-伊红(HE)染色,观察细胞形态.结果:齐多夫定浓度为3.3 mmol/L、四氯化碳浓度为2 mmol/L时,于6、12、24 h的吸光度(OD)值分别为(1.20±0.17)、(0.99±0.08)和(0.89±0.09)与(1.20±0.13)、(1.01±0.09)和(0.88±0.13),同时间点阴性对照组OD值分别为(1.34±0.08)、(1.11±0.10)和(1.03±0.11).与阴性对照组比较,齐多夫定组、四氯化碳组的细胞活力均显著降低,差异均有统计学意义(均P＜0.05),但10 mmol/L 齐多夫定对细胞活性的影响远低于10 mmol/L 四氯化碳.加3.3 mmol/L齐多夫定后6和12 h,AST释放量为(18.53±2.02) 卡门单位和(26.86±2.61) 卡门单位,ALT的释放量为(15.16±2.18)卡门单位和(27.48±2.27)卡门单位,LDH释放量为(1 681.00±193.98) U/L和(2 708.55±78.73)U/L;阴性对照组同时间点AST释放量为(15.91±1.62)卡门单位和(37.71±2.54) 卡门单位,ALT释放量为(19.66±0.74)卡门单位和(23.42±1.46)卡门单位,LDH释放量为(2 036.39±134.56) U/L和(2 870.21±87.73) U/L;与阴性对照组比较,齐多夫定对AST、ALT及LDH的释放量均有显著影响,差异均有统计学意义(均P＜0.05).齐多夫定浓度≥3.3 mmol/L时,可引起细胞膜破裂、核浓缩,四氯化碳浓度为10 mmol/L时,可使细胞变小、细胞膜破裂及核碎裂.结论:齐多夫定浓度≥3.3 mmol/L时,具有肝细胞毒性作用,齐多夫定的细胞毒性低于四氯化碳.     

依非韦伦的不良反应及用药护理

目的：探讨依非韦伦用于治疗艾滋病的不良反应,并进行相应的用药护理。方法：将2017年10月—2021年10月该院800例采用依非韦伦用于治疗艾滋病的患者作为研究对象,对服用过程中出现的不良反应事件进行汇总,并分析发生的临床特征。结果：800例患者中出现不良反应的为102例,占比12.75%。21～50岁服用依非韦伦后出现不良反应较多。服用依非韦伦0.5～1个月后,发生不良反应发生率最高,0～0.5个月后发生不良反应发生率次之,占比19.61%。服用依非韦伦后不良反应累及神经系统,主要表现为失眠、头痛等,占比28.33%,其次是皮肤及其附件,主要表现为全身性斑疹样皮疹、皮肤红肿等,占比22.50%。结论：服用依非韦伦后不同年龄可能出现不良反应程度不同,且不良反应发生的时间以及累及的器官/系统的占比不同,要密切关注依非韦伦的不良反应,保证患者用药安全性。     

番荔枝总内酯对大鼠心、肝和肾的毒性及其作用机制

目的观察番荔枝总内酯对大鼠的毒性作用,初步探讨其毒性机制。方法将雄性SD大鼠随机分为溶剂对照、番荔枝总内酯7和14 mg·kg-1组,分别ig给药,每天1次,连续4周,末次给药1h后取血,处死大鼠。HE染色观察大鼠心、肝和肾组织病理变化;全自动生化分析仪检测血清中丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、血清尿素氮(BUN)、肌酐(Cr)和肌酸激酶(CK)水平;BCA法、分光光度法和荧光素法分别测定心、肝和肾线粒体中蛋白质浓度、线粒体复合物Ⅰ活性和ATP含量;荧光探针法检测组织中Ca2+和活性氧类(ROS)浓度。结果番荔枝总内酯14mg·kg-1组大鼠肝组织中央静脉周围细胞轻微肿胀;与溶剂对照组比较,血清ALT,AST,BUN和CK水平显著升高,分别由溶剂对照组的(50.0±1.4)U.L-1,(126±11)U.L-1,(6.13±0.15)mmol·L-1和(293±13)U.L-1升高到(59.0±2.6)U.L-1(P<0.05),(176±12)U.L-1(P<0.05),(12.9±2.05)mmol·L-1(P<0.01)和(480±97)U.L-1(P<0.05),血清Cr水平无明显变化。心、肝和肾组织线粒体复合物Ⅰ活性分别由溶剂对照组的(22.6±4.9),(72±10)和(34±4)μmo.lg-1蛋白.min-1降低到(7.5±1.7),(54±10)和(26±6)μmo.lg-1蛋白.min-1(P<0.05,P<0.01);心、肝和肾组织ATP含量由溶剂对照组的(10.4±2.1),(6.8±1.6)和(12.5±3.4)nmo.l L-1降低至(2.2±3.4),(3.4±1.2)和(5.5±1.1)nmol·L-1(P<0.05,P<0.01);心肌细胞中Ca2+和ROS浓度增加,荧光强度分别由7.37±0.64和14.8±4.1增加到9.06±0.08和110.0±19.0(P<0.05,P<0.01),肝和肾细胞内Ca2+和ROS浓度无明显变化。番荔枝总内酯7mg·kg-1组上述指标无明显变化。结论番荔枝总内酯对大鼠心、肝和肾具有一定的毒性,其作用机制可能是降低心、肝和肾组织中线粒体复合物I的活性和ATP含量,升高组织细胞内Ca2+和ROS浓度,引起组织细胞损伤。     

对乙酰氨基酚对大鼠原代肝细胞及BRL-3A细胞的毒性作用比较

目的 建立大鼠原代肝细胞提取鉴定体系,比较对乙酰氨基酚(APAP)对大鼠原代肝细胞和永生化细胞BRL-3A的毒性作用。方法 采用胶原酶原位两步灌流法提取大鼠原代肝细胞,通过过碘酸雪夫染色(PAS)和肝细胞双核结构进行鉴定;CCK 8法测定APAP对大鼠原代肝细胞及BRL-3A细胞毒性作用的IC₅₀;光学显微镜透射电镜观察APAP对2种细胞的损伤情况;全自动生化分析仪测定细胞上清AST、ALT、LDH、ALP、ALB、BUN、TP、GLU 8项生化指标的变化。结果 PAS糖原染色鉴定获取的大鼠原代肝细胞,双核结构,细胞存活率浮动在80%~95%;最佳接种密度为60000/cm²,在第3~5天为对数生长期;APAP作用于大鼠原代肝细胞24 h的IC₅₀为18.03 mmol/L,95%置信区间为(17.28~18.81)mmol/L,作用于BRL-3A的IC₅₀为20.05 mmol/L,95%置信区间为(18.99~21.17)mmol/L;透射电镜结果显示,在30 mmol/L APAP作用下,2种细胞细胞器肿胀,核膜破裂,细胞膜边界模糊不清;与对照组比较,大鼠原代肝细胞分泌的天冬氨酸氨基转移酶(AST)、尿素氮(BUN)、葡萄糖(GLU)、碱性磷酸酶(ALP)、乳酸脱氢酶(LDH)随着APAP浓度增加产生显著变化,而BRL-3A细胞几乎所有的酶学指标变化均差异不显著。结论 与永生化细胞BRL-3A比较,大鼠原代肝细胞更能体现药物的肝脏毒性作用,但其体外培养存活时间较短;BRL-3A细胞缺少肝脏重要酶类,增加细胞内肝脏酶类是提升其作为肝脏毒性筛选模型的更好手段之一。     

基因多态性与利福平对依非韦伦的疗效影响

依非韦伦（efavirenz）是中国HIV-1感染者广泛使用的一线抗HIV-1治疗药物。该药的临床标准用量来源于以白种人为主的临床试验,考虑到人种的差异、病理生理及合并用药的不同等对依非韦伦药物动力学的影响,标准剂量的依非韦伦并不适合所有的患者。本文综述依非韦伦血药浓度与其不良反应和疗效的相关性,依非韦伦相关代谢酶的基因多态性、利福平对其血药浓度的影响,并总结了有关中国HIV-1感染者使用依非韦伦的相关研究等,希望为临床及科研工作者提供参考。     

SIRT1在丙戊酸对肝细胞毒性中的作用研究

目的探讨沉默信息调节因子1(SIRT1)在丙戊酸对肝脏Hep G2细胞毒性中的作用。方法在Hep G2细胞中,丙戊酸(2 mmol·L-1)孵育6、12、24、48 h,或丙戊酸(0.5、1、2 mmol·L-1)分别孵育48 h,通过Western blot方法检测丙戊酸对SIRT1蛋白表达的影响;通过瞬时转染SIRT1表达质粒和si-SIRT1,采用SRB方法,观察对SIRT1基因进行过表达和抑制后,丙戊酸对Hep G2细胞毒性的改变情况。结果丙戊酸对SIRT1的表达有抑制作用,且具有时间和剂量依赖性。过表达SIRT1后,Hep G2细胞对丙戊酸的毒性敏感性下降,转染前后IC50分别为(4.025±0.47)、(10.87±1.50)mmol·L-1;而干扰SIRT1后,Hep G2细胞对丙戊酸的毒性敏感性增加,转染前后IC50分别为(1.938±0.16)、(0.663±0.05)mmol·L-1。结论丙戊酸可抑制SIRT1的蛋白表达,并且过表达SIRT1可拮抗丙戊酸对肝细胞的毒性作用。     

基因多态性对HIV/AIDS患者依非韦伦血药浓度的影响

摘 要依非韦伦是抗逆转录病毒治疗中常用的一种非核苷类逆转录酶抑制药,推荐的有效治疗浓度范围为1～4mg·L-1。由于遗传、病理生理、合并用药等因素的影响,依非韦伦个体间血药浓度变异较大,部分使用标准剂量的患者不良反应增加,而另外一些患者却出现病毒学失败。CYP2B6 是依非韦伦主要的代谢同工酶,它也是依非韦伦血药浓度个体差异的关键决定因素,其516G>T基因型对药物代谢具有显著影响,常作为调整依非韦伦用量的参考依据。除CYP2B6以外可影响血药浓度的基因还包括CYP2A6、UGT2B7、ABCB1/MDR1等,但不同研究所得结论不尽一致。本文综述影响依非韦伦血药浓度的基因多态性的研究报道,以期能为药物治疗方案调整与个体化用药提供参考。     

Characterization of chemically induced hepatotoxicity in collagen sandwiches of rat hepatocytes.

It has been shown that hepatocytes cultured in a collagen sandwich configuration maintain cell viability, morphology, and drug metabolizing activities for several weeks. The purpose of this study was to characterize chemically induced general toxicity in this system by exposing hepatocytes to eight different hepatotoxic compounds. Cell function and viability was measured by analyzing the secretions of urea and albumin and the release of lactate dehydrogenase. Significant decreases in urea and albumin secretions were detected after treatments with 32 nM aflatoxin B(1) and 1 mM doses of cadmium and the alkylating agents N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and methyl methane sulfonate (MMS). However, no significant toxicity could be measured following exposures to 5 mM carbon tetrachloride, 1 mM N, N-dimethylformamide (DMF), 1 mM vinyl acetate, and 1 mM acetaminophen. Western blots of cell lysates showed that hepatocytes maintained CYP1A, 2B, 3A2 but gradually lost CYP2E1, which is the main metabolic enzyme for acetaminophen, carbon tetrachloride, and DMF. The metabolites of acetaminophen were identified using liquid chromatography and electrospray mass spectrometry. It was determined that the hepatocytes converted most of the acetaminophen to the glucuronide and sulfate metabolites and only formed a small amount of the glutathione adduct. This research shows that the collagen sandwich culture system can only be used selectively for detecting hepatotoxicity and for identifying major metabolites of xenobiotic compounds.     

Protective effect of dieckol against chemical hypoxia-induced cytotoxicity in primary cultured mouse hepatocytes

Hepatic ischemic injury is a major complication arising from liver surgery, transplantation, or other ischemic diseases, and both reactive oxygen species (ROS) and pro-inflammatory mediators play the role of key mediators in hepatic ischemic injury. In this study, we examined the effect of dieckol in chemical hypoxia-induced injury in mouse hepatocytes. Cell viability was significantly decreased after treatment with cobalt chloride (CoCl₂), a well-known hypoxia mimetic agent in a time- and dose-dependent manner. Pretreatment with dieckol before exposure to CoCl₂ significantly attenuated the CoCl₂-induced decrease of cell viability. Additionally, pretreatment with dieckol potentiated the CoCl₂-induced decrease of Bcl-2 expression and attenuated the CoCl₂-induced increase in the expression of Bax and caspase-3. Treatment with CoCl₂ resulted in an increased intracellular ROS generation, which is inhibited by dieckol or N-acetyl cysteine (NAC, a ROS scavenger), and p38 MAPK phosphorylation, which is also blocked by dieckol or NAC. In addition, dieckol and SB203580 (p38 MAPK inhibitor) increased the CoCl₂-induced decrease of Bcl-2 expression and decreased the CoCl₂-induced increase of Bax and caspase-3 expressions. CoCl₂-induced decrease of cell viability was attenuated by pretreatment with dieckol, NAC, and SB203580. Furthermore, dieckol attenuated CoCl₂-induced COX-2 expression. Similar to the effect of dieckol, NAC also blocked CoCl₂-induced COX-2 expression. Additionally, CoCl₂-induced decrease of cell viability was attenuated not only by dieckol and NAC but also by NS-398 (a selective COX-2 inhibitor). In conclusion, dieckol protects primary cultured mouse hepatocytes against CoCl₂-induced cell injury through inhibition of ROS-activated p38 MAPK and COX-2 pathway.     

Cellular toxicity of hydrazine in primary rat hepatocytes.

Hydrazine (HzN) is an aircraft fuel and propellant used by the U.S. Air Force. The current study was undertaken to evaluate the acute toxicity of HzN in primary rat hepatocytes in vitro with reference to oxidative stress. The effects of short-term exposure (4 h) of hepatocytes to HzN were investigated with reference to viability, mitochondrial function, and biomarkers of oxidative stress. The viability data showed an increase in lactate dehydrogenase leakage and a decrease in mitochondrial activity with increasing concentration of HzN. The results of studies of oxidative stress biomarkers showed a depletion of reduced glutathione (GSH) and an increase in oxidized GSH, increased reactive oxygen species generation, lipid peroxidation, and reduced catalase activity. Furthermore, depletion of GSH and catalase activity in hepatocytes by buthionine sulfoximine and 3-amino triazole, respectively, prior to exposure to HzN, increased its toxicity. The results suggest that acute HzN-induced cytotoxicity in rat hepatocytes is likely to be mediated through oxidative stress.     

六价铬对肝细胞内活性氧和腺苷酸转运体1转录水平的影响

目的探讨重金属六价铬[Cr(Ⅵ)]的体外肝毒性。方法 L-02肝细胞经Cr(Ⅵ)0,2,4,8,16和32μmol.L-1分别染毒12,24或36 h后,采用逆转录-荧光定量聚合酶链反应(RT-qPCR)和荧光光度法分别对腺苷酸转运体1(ANT1)mRNA表达水平和活性氧簇(ROS)水平进行检测。结果 Cr(Ⅵ)32μmol.L-1处理细胞12和24 h后,ROS水平明显升高,而处理36 h后,ROS水平明显下降。Cr(Ⅵ)2～32μmol.L-1处理细胞12和24 h后,细胞内ANT1 mRNA呈明显低表达水平,而处理36 h后,细胞内ANT1 mRNA表达水平明显增高,达正常对照组的2倍左右。结论 Cr(Ⅵ)在早期(12,24 h)可使L-02肝细胞内ROS水平升高,发生氧化应激,在后期(36 h)可诱导ANT1 mRNA表达水平升高,发生能量代谢应激,可能是Cr(Ⅵ)诱导细胞线粒体损伤的分子毒性机制之一。     

Proteomic alterations in mouse kidney induced by andrographolide sodium bisulfite

Aim:

To identify the key proteins involved in the nephrotoxicity induced by andrographolide sodium bisulfite (ASB).

Methods:

Male ICR mice were intravenously administrated with ASB (1000 or 150 mg·kg⁻¹·d⁻¹) for 7 d. The level of malondialdehyde (MDA) and the specific activity of superoxide dismutase (SOD) in kidneys were measured. The renal homogenates were separated by two-dimensional electrophoresis, and the differential protein spots were identified using a matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF)/TOF mass spectrometry.

Results:

The high dose (1000 mg/kg) of ASB significantly increased the MDA content, but decreased the SOD activity as compared to the control mice. The proteomic analysis revealed that 6 proteins were differentially expressed in the high-dose group. Two stress-responsive proteins, ie heat shock cognate 71 kDa protein (HSC70) and peroxiredoxin-6 (PRDX6), were regulated at the expression level. The remaining 4 proteins involving in cellular energy metabolism, including isoforms of methylmalonyl-coenzyme A mutase (MUT), nucleoside diphosphate-linked moiety X motif 19 (Nudix motif19), mitochondrial NADH dehydrogenase 1 alpha subcomplex subunit 10 (NDUFA10) and nucleoside diphosphate kinase B (NDK B), were modified at the post-translational levels.

Conclusion:

Our findings suggest that the mitochondrion is the primary target of ASB and that ASB-induced nephrotoxicity results from oxidative stress mediated by superoxide produced by complex I.     

Possible involvement of active oxygen species in selenite toxicity in isolated rat hepatocytes

Mechanisms of selenite cytotoxicity were examined using isolated rat hepatocytes. When selenite was added to a suspension of rat hepatocytes, intracellular reduced glutathione (GSH) was decreased and the oxygen consumption rate was increased. Subsequently, thiobarbituric acid-reactive substances (TBA-RS) and lactate dehydrogenase (LDH) leakage were increased. A ferric iron chelator, desferrioxamine (DF), and a synthetic Superoxide dismutase (SOD) mimic, desferrioxamine manganese (DFMn), reduced the selenite toxicity. These results suggest that Superoxide anion and its reactive metabolites such as the hydroxyl radical may be involved in the cytotoxicity of selenite.     

依非韦伦的合成工艺研究

目的依非韦伦合成工艺的优选。方法以N-(4’-甲氧苄基)-4-氯-(三氟乙酰基)苯胺为原料,经炔基化、脱保护、环化三步反应制备依非韦伦。结果合成了具有良好化学纯和光学纯的依非韦仑(纯度99.5%;ee值99.9%,总产率69%)。结论得到了一种实用的、不对称合的成依非韦伦的途径,使得这种重要的化合物可用于工业化生产。     

A review on proteomics analysis to reveal biological pathways and predictive proteins in sulfur mustard exposed patients: roles of inflammation and oxidative stress

Sulfur mustard (SM) is a mutagenic compound that targets various organs. Although it causes a wide range of abnormalities, cellular and molecular mechanisms of its action are not-well-understood. Oxidation of DNA, proteins, lipids, as well as depletion of cellular nicotinamide adenine dinucleotide (NAD), antioxidants and increase of intracellular calcium are the hypothesized mechanisms of its action at the acute phase of injury. In this review, the proteome analysis of SM toxicity has been considered. We selected articles that considered proteomics analysis of SM toxicity with two-dimensional gel electrophoresis (2DE) followed by mass spectrometry. Our search yielded nine related articles, four original in vitro and five human studies. The results of these studies have revealed a change in expression pattern of various proteins such as haptoglobin, amyloid A1, surfactant proteins, S100 proteins, apolipoprotein, Vit D binding protein, transferrin, alpha 1 antitrypsin, protein disulfide isomerase and antioxidant enzymes in patients who were exposed to SM about 30 years ago. Most of these proteins are up- or down-regulated in response to excessive production of reactive oxygen species (ROS) and oxidative stress (OS). There is a tight link between the expression pattern of these proteins with accumulation of leukocytes, inflammatory conditions, antioxidant depletion, mitochondrial deficiency, as well as increased expression or activity of several proteases such as caspases and matrix metalloproteinases (MMPs). Therefore, excessive production of ROS and OS along with chronic inflammatory may be the long-term toxic effects of SM following acute exposure.     

Pharmacokinetic interactions of efavirenz and voriconazole in healthy volunteers

AIMS

Co-administration of standard-dose voriconazole and efavirenz results in a substantial decrease in voriconazole levels, while concurrently increasing efavirenz levels. Hence, concomitant use of standard doses of these drugs was initially contraindicated. This study assessed different dose combinations of efavirenz and voriconazole, with the goal of attaining a dose combination that provides systemic exposures similar to standard-dose monotherapy with each drug.

METHODS

This was an open-label, four-treatment, multiple-dose, fixed-sequence study in 16 healthy males. Steady-state pharmacokinetics were assessed following two test treatments (voriconazole 300 mg q12 h + efavirenz 300 mg q24 h and voriconazole 400 mg q12 h + efavirenz 300 mg q24 h) and compared with standard-dose monotherapy (voriconazole 200 mg q12 h or efavirenz 600 mg q24 h).

RESULTS

Dose adjustment to voriconazole 300 mg q12 h with efavirenz 300 mg q24 h decreased voriconazole area under the concentration–time curve (AUC_τ) and maximum concentration (C_max), with changes of −55% [90% confidence interval (CI) −62, −45] and −36% (90% CI −49, −21), respectively, when compared with monotherapy. Voriconazole 400 mg q12 h plus efavirenz 300 mg q24 h decreased voriconazole AUC_τ (−7%; 90% CI −23, 13) and increased C_max (23%; 90% CI −1, 53), while increasing efavirenz AUC_τ (17%; 90% CI 6, 29) and not changing C_max when compared with the respective monotherapy regimens. No serious adverse events were observed with voriconazole plus efavirenz.

CONCLUSIONS

When co-administered, voriconazole dose should be increased to 400 mg q12 h and efavirenz dose decreased to 300 mg q24 h in order to provide systemic exposures similar to standard-dose monotherapy.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Efavirenz 400 mg q24 h reduces exposure to voriconazole 200 mg q12 h when the two drugs are co-administered.
• Furthermore, voriconazole increases the systemic exposure of efavirenz.
• Co-administration was therefore initially contraindicated.

WHAT THIS STUDY ADDS

• The doses of efavirenz and voriconazole can be adjusted to provide adequate exposure to both drugs when the two are co-administered, without compromising safety.
• Appropriate adjustment of doses for both drugs may thus represent an alternative to a mere contraindication.

     

Discriminating redox cycling and arylation pathways of reactive chemical toxicity in trout hepatocytes.

The toxicity of four quinones, 2,3-dimethoxy-1,4-naphthoquinone (DMONQ), 2-methyl-1,4-naphthoquinone (MNQ), 1,4-naphthoquinone (NQ), and 1,4-benzoquinone (BQ), which redox cycle or arlyate in mammalian cells, was determined in isolated trout (Oncorhynchus mykiss) hepatocytes. More than 70% of cells died in 3 h when exposed to BQ or NQ; 50% died in 7 h when exposed to MNQ, with no mortality compared to controls after 7 h DMONQ exposure. A suite of biochemical parameters was assessed for ability to discriminate these reactivity pathways in fish. Rapid depletion of glutathione (GSH) with appearance of glutathione disulfide (GSSG) and increased dichlorofluoroscein fluorescence were used as indicators of redox cycling, noted with DMONQ, MNQ, and NQ. Depletion of GSH with no GSSG accumulation, and loss of free protein thiol (PrSH) groups (nonreducible) indicated direct arylation by BQ. All toxicants rapidly oxidized NADH, with changes in NADPH noted later (BQ, NQ, MNQ) or not at all (DMONQ). Biochemical measures including cellular energy status, cytotoxicity, and measures of reactive oxygen species, along with the key parameters of GSH and PrSH redox status, allowed differentiation of responses associated with lethality. Chemicals that arylate were more potent than redox cyclers. Toxic pathway discrimination is needed to group chemicals for potency predictions and identification of structural parameters associated with distinct types of reactive toxicity, a necessary step for development of mechanistically based quantitative structure-activity relationships (QSARs) to predict chemical toxic potential. The commonality of reactivity mechanisms between rodents and fish was also demonstrated, a step essential for species extrapolations.