In Vitro ADMET Laboratories LLC, 9221 Rumsey Road, Columbia, MD 21045, USA.
In Vitro ADMET Laboratories LLC, 9221 Rumsey Road, Columbia, MD 21045, USA.
Chem Biol Interact. 2016 Aug 5;255:12-22. doi: 10.1016/j.cbi.2015.12.013. Epub 2015 Dec 21.
A possible risk factor for drug-induced hepatotoxicity is drug metabolizing enzyme activity, which is known to vary among individuals due to genetic (genetic polymorphism) and environmental factors (environmental pollutants, foods, and medications that are inhibitors or inducers of drug metabolizing enzymes). We hypothesize that hepatic cytochrome P450-dependent monooxygenase (CYP) activity is one of the key risk factors for drug induced liver injuries (DILI) in the human population, especially for drugs that are metabolically activated to cytotoxic/reactive metabolites. Human hepatocytes from 19 donors were evaluated for the activities of 8 major P450 isoforms: CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4. Extensive individual variations were observed, consistent with what is known to be in the human population. As CYP3A4 is known to be one of the most important P450 isoforms for drug metabolism, studies were performed to evaluate the relationship between the in vitro cytotoxicity of hepatotoxic drugs and CYP3A4 activity. In a proof of concept study, hepatocytes from six donors (lots) representing the observed range of CYP3A4 activities were chosen for the evaluation of in vitro hepatotoxicity of four drugs known to be associated with acute liver failure: acetaminophen, cyclophosphamide, ketoconazole, and tamoxifen. The hepatocytes were cultured in collagen-coated plates and treated with the hepatotoxicants for approximately 24 h, followed by viability determination based on cellular adenosine triphosphate (ATP) contents. HH1023, the lot of hepatocytes with the highest CYP3A4 activity, was found to be the most sensitive to the cytotoxicity of all 4 hepatotoxic drugs, thereby suggesting that high CYP3A4 activity may be a risk factor. To further validate the relationship, a second study was performed with hepatocytes from 16 donors. In this study, the hepatocytes were quantified for CYP3A4 activity at the time of treatment. Results of the second study show confirm the correlation between with high CYP3A4 activity and sensitivity to hepatotoxic drugs. Our results with primary cultured hepatocytes from multiple donors support the hypothesis that elevated P450 activity may be a risk factor for drug-induced liver injuries.
药物诱导的肝毒性的一个可能的危险因素是药物代谢酶活性，由于遗传（遗传多态性）和环境因素（环境污染物、食物以及抑制或诱导药物代谢酶的药物），这种活性在个体之间存在差异。我们假设肝微粒体细胞色素 P450 依赖性单加氧酶（CYP）活性是人群中药物性肝损伤（DILI）的关键危险因素之一，特别是对于那些代谢激活为细胞毒性/反应性代谢物的药物。对 19 位供体的人原代肝细胞进行了 8 种主要 CYP 同工酶（CYP1A2、CYP2B6、CYP2C8、CYP2C9、CYP2C19、CYP2D6、CYP2E1 和 CYP3A4）活性的评估。观察到个体间存在广泛的差异，这与已知的人类情况一致。由于 CYP3A4 被认为是药物代谢最重要的 P450 同工酶之一，因此进行了研究以评估肝毒性药物的体外细胞毒性与 CYP3A4 活性之间的关系。在概念验证研究中，选择了来自六个供体（批次）的肝细胞进行体外评估，这些供体代表了观察到的 CYP3A4 活性范围，这些肝细胞用于评估四种已知与急性肝衰竭相关的药物的体外肝毒性：对乙酰氨基酚、环磷酰胺、酮康唑和他莫昔芬。肝细胞在胶原包被的平板中培养，并在大约 24 小时内用肝毒性药物处理，然后基于细胞三磷酸腺苷（ATP）含量测定细胞活力。发现具有最高 CYP3A4 活性的 HH1023 对所有 4 种肝毒性药物的细胞毒性最敏感，这表明高 CYP3A4 活性可能是一个危险因素。为了进一步验证这种关系，进行了第二项涉及 16 位供体的肝细胞的研究。在这项研究中，在治疗时对肝细胞的 CYP3A4 活性进行了定量。第二项研究的结果证实了高 CYP3A4 活性与肝毒性药物敏感性之间的相关性。来自多个供体的原代培养肝细胞的结果支持这样一种假设，即升高的 P450 活性可能是药物性肝损伤的危险因素。
