Is plasma β-glucuronidase a novel human biomarker for monitoring anticholinesterase pesticides exposure? A Malaysian experience

A cross-sectional study was conducted to investigate the effects of acute and chronic pesticide exposure on the plasma β-glucuronidase enzyme activity among five patients of acute pesticide poisoning in Tengku Ampuan Rahimah Hospital, Klang, 230 farmers in the MADA area, Kedah and 49 fishermen in Setiu, Terengganu. The duration of pesticide exposure among the patients was unknown, but the plasma samples from patients were collected on day one in the hospital. The duration of pesticide exposure among the farmers was between 1 and 45 years. The β-glucuronidase activity was compared with plasma cholinesterase activity in the same individual. The plasma cholinesterase activity was measured using Cholinesterase (PTC) Reagent set kit (Teco Diagnostics, UK) based on colorimetric method, while the plasma β-glucuronidase activity was measured fluorometrically based on β-glucuronidase assay. The plasma cholinesterase activity was significantly reduced (p < 0.05) among the patients (1386.786 ± 791.291 U/L/min) but the inhibition in plasma cholinesterase activity among the farmers (7346.5 ± 1860.786 U/L/min) was not significant (p > 0.05). The plasma β-glucuronidase activity among the farmers was significantly elevated (p < 0.05) (0.737 ± 0.425 μM/h) but not significant among the patients (p > 0.05). The plasma cholinesterase activity was positively correlated with the plasma β-glucuronidase activity among the farmers (r = 0.205, p < 0.01) but not among the patients (r = 0.79, p > 0.05). Thus, plasma β-glucuronidase enzyme activity can be measured as a biomarker for the chronic exposure of pesticide. However, further studies need to be performed to confirm whether plasma β-glucuronidase can be a sensitive biomarker for anticholinesterase pesticide poisoning.