Proteomic analysis of dried blood spots for biomonitoring organophosphorus exposures.
Marsillach Lopez J; Hsieh EJ; Richter RJ; MacCoss MJ; Hoofnagle AN; Furlong CE
Toxicologist 2014 Mar; 138(1):26
Organophosphorus (OP) compounds are involved in most of the occupational and environmental intoxications reported worldwide. They inhibit cholinesterases and other serine hydrolases, leading to neurological damage and serious health effects. The standard methods used for biomonitoring OP exposures are the Ellman assays, which measure the enzymatic activity of either red blood cell (RBC) acetylcholinesterase or plasma butyrylcholinesterase (BChE). Despite being fast and inexpensive, these assays suffer from several drawbacks. We have developed a rapid immunomagnetic bead (IMB) purification for biomarkers of OP exposure, followed by OP-adduct identification on active site serines by high-resolution mass spectrometry (MS). The IMB-MS methods have been adapted to identify OP insecticide adducts on both plasma BChE and RBC acylpeptide hydrolase (APH), two known biomarkers of OP exposure. Plasma, RBCs or dried blood spots (DBS) are used for our IMB-MS methods. The methods have been designed for adaptation to high-throughput protocols to facilitate their transfer to clinical laboratories. These methods will be validated using a cohort of Washington State agricultural workers with characterized OP exposures to chlorpyrifos or azinphos-methyl. The IMB protocols purify BChE and APH from as low as 25 uL of plasma or RBCs, respectively, or from DBS. The use of DBS will facilitate sample collection, shipping, and archiving as well as the analysis of already archived samples. The IMB-MS protocols have significant advantages: they do not require a pre-exposure measurement, they can detect low levels of exposure, they can be automated, and they provide information on both the OP and percentage modification of the active site serines.
Toxicology; Nanotechnology; Organo-phosphorus-compounds; Cholinesterase-inhibitors; Neurological-system; Exposure-levels; Analytical-processes; Biomarkers; Insecticides; Agriculture
Agriculture, Forestry and Fishing
The Toxicologist. Society of Toxicology 53rd Annual Meeting and ToxExpo, March 23-27, 2014, Phonex, Arizona
University of Washington