Intraindividual Stability of Human Erythrocyte Cholinesterase Activity

Abstract

Background: Erythrocyte cholinesterase (RBC-ChE) activities serve as useful and sensitive biomarkers to monitor exposure to cholinesterase-inhibiting substances, such as chemical warfare nerve agents and pesticides. Although the interindividual variation of RBC-ChE is well characterized, the magnitude of intraindividual variation for RBC-ChE remains controversial. An accurate measure of intraindividual variation is critical for establishing the appropriate frequency of RBC-ChE testing. Methods: We retrospectively tracked the intraindividual variation of RBC-ChE activities among 46 male nerve agent workers from a single US Army depot that participated in a medical surveillance program requiring periodic RBC-ChE monitoring. All RBC-ChE analysis was performed by the same medical laboratory technician by the delta pH method. Results: A mean of 38 and a median of 37 RBC-ChE measurements were available for each worker. The mean duration of employment for these workers was 20 years (median, 21 years). The mean CV for RBC-ChE in this set of 46 workers was 3.9%. Linear regression analysis of the data for each worker resulted in a mean slope of 0.0010 delta pH units/h per year. Conclusions: RBC-ChE activities increased in each person by a mean of 0.01 delta pH units/h every 10 years, which is a negligible rate. These findings highlight the

Longitudinal Assessment of Blood Cholinesterase Activities Over 2 Consecutive Years Among Latino Nonfarmworkers and Pesticide-Exposed Farmworkers in North Carolina

“…Similarly, carbamate pesticides covalently bind cholinesterases, but generally lead to more rapidly reversible inhibition than with the organophosphorus pesticides. These and other issues, such as the wide range of normal values in levels of cholinesterases, 13 provide a rationale for repeated measures across time in assessing depression in cholinesterase activities.…”

Acetylcholinesterase Activity and Neurodevelopment in Boys and Girls

“…Next, erythrocytic AChE is similar to neuronal AChE activity, 2 and brain AChE has been reported to be diminished after chlorpyrifos exposure in rats. [16][17][18][19][20] In addition, erythrocytic AChE has a long recovery time (82 days), 21 low intraindividual variability, 22 and is considered to be a stable assessment of past exposures to cholinesterase inhibitors, 23 although it is less sensitive and specific than most pesticide quantification methods. 23,24 Finally, we previously found that a single measure of AChE activity can be an adequate indicator of pesticide exposure in epidemiologic studies of children.…”

The Red Blood Cell Acetylcholinesterase Levels of Depressive Patients with Suicidal Behavior in an Agricultural Area

“…Erythrocytic and neuronal AChE has similar activity and brain AChE has been reported to be derogated after chlorpyrifos exposure in rats [14,32]. And also erythrocytic AChE has a long salvage time (82 days) [15], intraindividual changeability is low [40], is taken into account as a stable appraisal of past exposures to cholinesterase inhibitors [41]. In epidemiologic studies it is reported that a single measure of AChE activity can be an adequate indicator of pesticide exposure [42].…”