ToxSci Advance Access published online on January 16, 2009
Toxicological Sciences, doi:10.1093/toxsci/kfp009
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First identification of the hepatotoxic microcystins in the serum of a chronically exposed human population together with indication of hepatocellular damage
State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, P. R. China
* Corresponding author: Dr. Ping Xie, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan 430072, P. R. China. Tel & Fax: +86-27-68780622. E-mail: xieping{at}ihb.ac.cn
Received November 26, 2008; revision received January 7, 2009; accepted January 7, 2009
| Abstract |
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Hapatotoxic microcystins (MCs) are the most commonly reported cyanotoxins in eutrophic freshwaters. In 1996, human intoxications by MCs caused deaths of 76 patients at Caruaru dialysis centers in Brazil. So far, there have been no direct evidences of MC occurrence in human tissue in consequence of exposure to MC. In this study, we improved cleanup procedures for detecting MCs in serum sample using LC/MS, and confirmed for the first time the presence of MCs in serum samples (average 0.39 ng/ml, which amounts to ca. 1/87 of the concentrations found in tissue samples of the Caruaru victims) of fishermen at Lake Chaohu. Daily intake by the fishermen was estimated to be in the range of 2.2-3.9 µg MC-LReq, whereas the provisional WHO TDI for daily lifetime exposure is 0.04 µg/kg or 2-3 µg per person. Moreover, statistical analysis (PCCA) showed closer positive relationships between MC serum concentrations and concentrations of ALT, AST, LDH, and ALP than between the MC concentrations and other biochemical indicators. Thus, the data raise the question whether extended exposure in the range of the TDI or up to a factor of 10 above it may already lead to indication of liver damage. The results also demonstrate a risk of health effects from chronic exposure to microcystins at least for populations with high levels of exposure, like these fishermen.
Key Words: Serum microcystins; Serum biochemical indices; Natural chronic exposure; Fishermen; Hepatocellular damage.