Turner P C, Dingley K H, Coxhead J, Russell S, Garner C R
The Jack Birch Unit for Environmental Carcinogenesis, Department of Biology, University of York, Heslington, United Kingdom.
Cancer Epidemiol Biomarkers Prev. 1998 May;7(5):441-7.
This study aimed to estimate aflatoxin B1 (AFB1) exposure in the United Kingdom population by measuring levels of serum AFB1-albumin (alb), using immunoassay and high-performance liquid chromatography (HPLC) with fluorescence detection. A self-questionnaire on dietary habits from 104 volunteers (47 men and 57 women) in York was completed, and blood samples were collected. Serum alb was extracted, and AFB1-lysine (lys), the digest product of AFB1-alb, was isolated and measured. A sensitive ELISA (detection limit, approximately 1.4 pg of AFB1-lys) was developed. A good correlation was found between calibration of ELISA results and scintillation counting, for rats dosed with [3H]AFB1 (r = 0.972; P < 0.001). This ELISA was subsequently used to analyze human serum alb. For United Kingdom human sera, the mean adduct levels were 29.3 +/- 14.8 pg AFB1-lys equivalents (eq) mg albumin (males) and 26.9 +/- 14.4 pg AFB1-lys eq/mg alb (females). Confirmation of the ELISA data was sought using reversed-phase HPLC with fluorescence detection. HPLC chromatograms of digested York serum alb were compared to digested serum alb for humans from Qidong County, People's Republic of China, and from AFB1-dosed rats. These all gave similar HPLC profiles. Each sample contained fluorescent material that coeluted with and just before the AFB1-lys standard. Fluorescent fractions were found to be inhibitory in a separate anti-AFB1-lys ELISA, indicating that these earlier fluorescent peaks contained AFB1 residues. Our results suggest that measurable internal AFB1 exposure may be occurring in some United Kingdom individuals, albeit at lower levels than those seen for areas with high AFB1 exposure. The source of this exposure may reflect the known difficulties in accurately monitoring regulated imported foodstuffs and/or the lack of regulations on other potentially contaminated imports. However, no positive correlations were found between our AFB1-lys measurements and any dietary questionnaire information. Animal studies, as well as human studies, have been important in developing exposure and internal adduct relationships in humans. Based on this literature, our AFB1-alb data indicate a mean daily exposure of 3 microg of AFB1 and a mean internal dose in liver DNA of 5.9 adducts/10(7) nucleotides. We believe this may be an overestimate of the AFB1 exposure level in the United Kingdom, and further studies are needed to accurately relate external dose and internal AFB1 biomarkers in humans.
本研究旨在通过使用免疫测定法和带荧光检测的高效液相色谱法（HPLC）测量血清黄曲霉毒素B1-白蛋白（alb）水平，来估算英国人群的黄曲霉毒素B1（AFB1）暴露量。完成了一份针对约克郡104名志愿者（47名男性和57名女性）饮食习惯的自填式问卷，并采集了血样。提取血清alb，分离并测量AFB1-alb的消化产物AFB1-赖氨酸（lys）。开发了一种灵敏的酶联免疫吸附测定法（ELISA）（检测限约为1.4 pg AFB1-lys）。对于用[3H]AFB1给药的大鼠，ELISA结果校准与闪烁计数之间发现了良好的相关性（r = 0.972；P < 0.001）。该ELISA随后用于分析人类血清alb。对于英国人体血清，平均加合物水平为29.3 +/- 14.8 pg AFB1-lys当量（eq）/mg白蛋白（男性）和26.9 +/- 14.4 pg AFB1-lys eq/mg alb（女性）。使用带荧光检测的反相HPLC来寻求对ELISA数据的确认。将约克郡血清alb消化后的HPLC色谱图与来自中国启东县的人类以及AFB1给药大鼠的消化后血清alb的色谱图进行比较。这些都给出了相似的HPLC图谱。每个样品都含有与AFB1-lys标准品共洗脱且在其之前洗脱的荧光物质。在单独的抗AFB1-lys ELISA中发现荧光级分具有抑制作用，表明这些较早的荧光峰含有AFB1残基。我们的结果表明，在一些英国个体中可能发生了可测量的体内AFB1暴露，尽管其水平低于AFB1高暴露地区所见的水平。这种暴露的来源可能反映了在准确监测受监管的进口食品方面已知的困难和/或对其他潜在受污染进口品缺乏监管。然而，在我们的AFB1-lys测量值与任何饮食问卷信息之间未发现正相关。动物研究以及人体研究对于建立人类暴露与体内加合物关系一直很重要。基于该文献，我们的AFB1-alb数据表明平均每日AFB1暴露量为3微克，肝脏DNA中的平均体内剂量为5.9个加合物/10^7个核苷酸。我们认为这可能高估了英国的AFB1暴露水平，需要进一步研究以准确关联人类的外部剂量和体内AFB1生物标志物。
