Development of Methods for Establishing a Global Network for Aflatoxin Exposure
The goals of this project were to broaden the understanding of aflatoxin (AF) exposure and the connection to epidemiology using biomarkers. While contamination by the AF-producing molds may be universal within a given geographical area, the levels or final concentration of AFs in the grain product can vary from < 1 µg/kg (1 ppb) to > 12,000 µg/kg (12ppm). For this reason, many researchers agree that the measurement of human exposure to aflatoxins using biomarkers is more practical than using food contamination and consumption data.
The biomarker analysis technology previously developed was used to determine aflatoxin biomarker levels in blood serum from subjects in the West African countries of Burkina Faso and Ghana. The technology is a highly sensitive, non-antibody, non-radioactive and non-mass spectrometry based analytical method for rapidly measuring, at low cost, serum and urine aflatoxin B1 (AFB1), lysine (AFB-LYS), and fumonisin (FN) biomarkers using HPLC technologies. One of the novel achievements of the project was the establishment of the capacity for estimation in food, as well as biomarker based, of aflatoxin and fumonisin exposure at the Noguchi Medical Research Laboratory, in Accra, Ghana.
During 2011, animal studies were conducted to validate the newly developed method for measurement of AFB- LYS, and to explore immune toxic effects of aflatoxin exposure in animals treated with single dose and repeated doses. Detailed data analyses reported in 2012 demonstrates that liver GST-P+ cells and foci are sensitive biomarkers for AFB1 toxic effect and correlated with bile duct proliferation and biochemical alterations in F34 rats, which hold promise as potential target for future intervention strategies. AFB1-lysine adduct samples over several years were analyses on samples in Uganda in cooperation with the British Medical Research Council/Uganda Unit and RAKAI Health Program, which clearly demonstrated temporal pattern of aflatoxin exposure in rural human populations in Uganda. Co-contamination of aflatoxin and fumonisin in food and human dietary exposure was determined in residents in three different areas of China, and co-contamination was found in corn, rice, and wheat flour. Based on measured food consumption data, the co-exposure to aflatoxin and fumonisin in residents of rural China may contribute to the etiology of human chronic diseases in high-risk areas.
Dr. Jia-Sheng Wang
Kwame Nkrumah University of Science and Technology
- Dr. William Otoo Ellis
Texas A and M University
- Dr. Timothy Phillips
University of Alabama at Birmingham
- Dr. Pauline E. Jolly
University of Georgia
- Ms. Chryssi Laguines