剂量反应评估的主要功能是估计目标人群的“安全”剂量,以支持化学风险评估。通常,根据两步程序,针对癌症和非癌症影响开发了不同的“安全”剂量,即,出发点(POD)推导和低剂量外推。然而,当前的剂量-反应评估框架因其二分法策略而没有整合作用模式(MOA)信息而受到批评.这项研究的目的是,根据我们以前的工作,开发基于MOA的概率剂量反应框架,该框架在剂量反应建模过程中定量合成生物途径,以估计具有致癌潜力的化学物质的风险。3,3\',4,4\',举例说明了5-五氯联苯(PCB-126),以证明我们提出的方法。新的建模框架有四个主要步骤,包括(1)关键可量化事件(KQE)的识别和提取,(2)必要剂量计算,(3)基于MOA的POD推导,和(4)基于MOA的概率参考剂量(RfD)估计。与报道的POD和传统RFD相比,从我们的方法得出的基于MOA的估计是可比和合理的。我们方法的一个关键特征是使用总体MOA信息来建立包括低剂量区域在内的整个剂量连续体的剂量反应关系。另一方面,通过以概率的方式调整不确定性和可变性,基于MOA的概率RFD可以为特定人口比例的健康保护提供有用的见解。此外,拟议的框架具有重要的潜力,可以推广到评估非致突变致癌物以外的不同类型的化学物质,强调其对改善当前化学品风险评估的效用。
A main function of dose-response assessment is to estimate a \"safe\" dose in the target population to support chemical risk assessment. Typically, a \"safe\" dose is developed differently for cancer and noncancer effects based on a 2-step procedure, ie, point of departure (POD) derivation and low-dose extrapolation. However, the current dose-response assessment framework is criticized for its dichotomized strategy without integrating the mode of action (
MOA) information. The objective of this study was, based on our previous work, to develop a
MOA-based probabilistic dose-response framework that quantitatively synthesizes a biological pathway in a dose-response modeling process to estimate the risk of chemicals that have carcinogenic potential. 3,3\',4,4\',5-Pentachlorobiphenyl (PCB-126) was exemplified to demonstrate our proposed approach. There were 4 major steps in the new modeling framework, including (1) key quantifiable events (KQEs) identification and extraction, (2) essential dose calculation, (3) MOA-based POD derivation, and (4)
MOA-based probabilistic reference dose (RfD) estimation. Compared with reported PODs and traditional RfDs, the
MOA-based estimates derived from our approach were comparable and plausible. One key feature of our approach was the use of overall MOA information to build the dose-response relationship on the entire dose continuum including the low-dose region. On the other hand, by adjusting uncertainty and variability in a probabilistic manner, the
MOA-based probabilistic RfDs can provide useful insights of health protection for the specific proportion of population. Moreover, the proposed framework had important potential to be generalized to assess different types of chemicals other than nonmutagenic carcinogens, highlighting its utility to improve current chemical risk assessment.