真菌毒素中长效暴露标志物的筛查确证及暴露评估应用探索研究

Mycotoxins are among the most important natural contaminants found in foodstuffs, posing a serious threat to the food safety and human health. The heterogeneous temporal distribution of mycotoxin in foods leads to the difficulty in its exposure assessment, since the current methods in use could only reflect the short-term exposure before sampling, while the requirement for medium- and long-term exposure assessment is still not fulfilled. This study will focus on the solution to the medium- and long-term exposure assessment of 5 mycotoxins as major food contaminants in China. First, on the basis of the current achievements in this field, human hepatocytes will be applied to the research on the metabolism of these mycotoxins, and together with stable isotope labeling and non-targeted screening by LC-HRMS, their metabolic pathways and metabolites will be carefully studied. Then the potential medium to long-term biomarkers of exposure will be selected from the metabolites and confirmed through analysis of liquid biological samples (e.g. blood, urine) and cumulative biological samples (e.g. hair, nail); and accurate qualitative and quantitative analysis methods for these biomarkers will also be established. With the study of 3-month duplicate portion of all the foods consumed by a small population, the quantitative relationship between the amounts of the medium to long-term biomarkers in biological samples and mycotoxins intake could be established, and subsequently an exposure assessment model. The outcome of the study could be applied in typical area to further improve and develop the model, which will finally introduce a novel strategy for medium- and long-term exposure assessment of mycotoxins based on medium to long-term biomarkers. This study is a frontier exploration on the methods for risk assessment of food contaminants, and the possibility to realize the medium- and long-term exposure assessment by single sampling of individual biological samples highlights its theory and practical significance.

真菌毒素是食品中重要的天然污染物，一直以来严重威胁食品安全和人类健康，其污染呈现显著的时间分布不均匀特征。而现有的评估方法仅能反映采样时间点附近的短期暴露情况，无法满足中长期暴露评估需求。为此，本研究拟着力解决真菌毒素暴露评估时间代表性不足的问题，以我国污染严重的主要真菌毒素为研究对象，充分利用现有成果，并补充开展人源肝细胞体外代谢非靶向筛查，建立较完善的毒素代谢产物数据库；从中筛选及确证液体生物样本（血液、尿液）和累积性生物样本（头发、指甲）中的真菌毒素中长效暴露标志物，建立痕量精准检测技术；进而通过小规模人群双份饭跟踪研究，明确标志物与毒素中长期膳食摄入之间的量化关系，建立暴露评估模型；并开展典型地区示范应用研究，创造性地发展基于中长效暴露标志物的真菌毒素中长期暴露评估新策略。这是我国对食品污染物风险评估方法的前沿探索，使一次采样实现中长期暴露评估成为可能，具有重要的理论与实际意义。

本研究围绕真菌毒素中长效暴露标志物及内暴露评估时间代表性问题，在全面解析我国12大类食品中43种真菌毒素的污染分布及暴露风险基础上，明确6类重点关注真菌毒素；优化构建永生化人源肝细胞体外代谢模型，结合高分辨质谱代谢物多模式组合筛查与同位素内标示踪比对确认，发现并鉴定了各毒素的氧化还原、酮式、分子内水解、脱亚甲基、乙酰化、去甲氧基、去环氧、甲基化、脱甲醇基、活性中间体、内酰胺键断裂、以及毒素原型与部分I相代谢产物的磺酸化、磷酸化、葡萄糖苷、葡萄糖醛酸结合态，共计代谢产物58种，其中11种为首次发现，并以化学衍生法制备代谢产物9种，进而构建基于实体代谢产物的精准色谱质谱数据库；在此基础上，分析代谢产物结构性质、代谢途径与代谢特征，预测排泄动力学，筛选黄曲霉毒素、赭曲霉毒素A经内源性大分子加合降解的中长效暴露标志物；建立血液、尿液、毛发等生物样本中真菌毒素及主要代谢物多组分游离态与总量精准检测技术，开展典型地区人群生物监测及双份饭研究，解析各类毒素内暴露评估适宜的生物标志物与相应生物载体，明确内外暴露相关性，并揭示青少年与其他年龄组间显著的代谢及排泄差异，研究首次发现毛发中赋存的杂色曲霉素，发展毛发作为累积性生物载体用于毒素中长期内暴露评估的新策略。本研究是对污染分布不均匀的真菌毒素暴露评估方法的前沿探索，为全国污染监测、毒素优先评估项目及标准制修订提供了关键技术与数据，也为隐蔽型毒素筛查预警、毒素代谢通路与健康效应等研究提供了可借鉴的成果和思路。本项目标注发表期刊论文9篇（其中SCI论文8篇），申请/授权专利3项，参编专著2部，参加国家标准制修订3项，受邀做国内外会议报告2次，培养硕士研究生2名。另有专利、文章和软著在整理中，将作为后续成果提交。