title: Sublethal microcystin exposure and biochemical outcomes among hemodialysis patients.
abstract: Cyanobacteria are commonly-occurring contaminants of surface waters worldwide. Microcystins, potent hepatotoxins, are among the best characterized cyanotoxins. During November, 2001, a group of 44 hemodialysis patients were exposed to microcystins via contaminated dialysate. Serum microcystin concentrations were quantified with enzyme-linked immunosorbent assay which measures free serum microcystin LR equivalents (ME). We describe serum ME concentrations and biochemical outcomes among a subset of patients during 8 weeks following exposure. Thirteen patients were included; 6 were males, patients' median age was 45 years (range 16-80), one was seropositive for hepatitis B surface antigen. The median serum ME concentration was 0.33 ng/mL (range: <0.16-0.96). One hundred thirty nine blood samples were collected following exposure. Patients' biochemical outcomes varied, but overall indicated a mixed liver injury. Linear regression evaluated each patient's weekly mean biochemical outcome with their maximum serum ME concentration; a measure of the extrinsic pathway of clotting function, prothrombin time, was negatively and significantly associated with serum ME concentrations. This group of exposed patients' biochemical outcomes display evidence of a mixed liver injury temporally associated with microcystin exposure. Interpretation of biochemical outcomes are complicated by the study population's underlying chronic disease status. It is clear that dialysis patients are a distinct 'at risk' group for cyanotoxin exposures due to direct intravenous exposure to dialysate prepared from surface drinking water supplies. Careful monitoring and treatment of water supplies used to prepare dialysate is required to prevent future cyanotoxin exposure events.
authors.affiliation: United States Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, North Carolina, United States of America. hilborn.e@epa.gov
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Hilborn
authors.forename: Raquel M
authors.initials: RM
authors.lastname: Soares
authors.forename: Jerome C
authors.initials: JC
authors.lastname: Servaites
authors.forename: Alvima G
authors.initials: AG
authors.lastname: Delgado
authors.forename: Valéria F
authors.initials: VF
authors.lastname: Magalhães
authors.forename: Wayne W
authors.initials: WW
authors.lastname: Carmichael
authors.forename: Sandra M F O
authors.initials: SM
authors.lastname: Azevedo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D056486:Chemical and Drug Induced Liver Injury / Q000097:blood; D005260:Female; D015312:Hemodialysis Solutions / Q000633:toxicity*; D006801:Humans; D016014:Linear Models; D008099:Liver / Q000187:drug effects / Q000293:injuries; D008297:Male; D008387:Marine Toxins; D052998:Microcystins / Q000097:blood / Q000633:toxicity*; D008875:Middle Aged; D006435:Renal Dialysis / Q000009:adverse effects; D055815:Young Adult
chemical_list: D015312:Hemodialysis Solutions; D008387:Marine Toxins; D052998:Microcystins; C057862:cyanoginosin LR
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