A meta-analysis of normal human blood cholinesterase activities determined by a modified electrometric method

Abstract

Measurements of blood cholinesterase (ChE) activities, including those of erythrocytes (EChE), plasma or serum (PChE), and whole blood (WBChE), are used to assess exposure to ChE-inhibiting pesticides. The purpose of this review was to report normal reference ChE activities in the blood of healthy adult humans, as determined by a modified electrometric method. We performed a systematic review following PRISMA guidelines. Single-group meta-analysis of means of PChE, EChE, and WBChE activities of adult healthy subjects was conducted using the random effects model. The programs used were Open-Meta Analyst and Meta-Essentials Version 1.5. Studies selected for analysis comprised 21, 19, and 4 reports of normal reference/baseline PChE, EChE, and WBChE activities in 690, 635, and 121 healthy adult males and/or females, respectively. The meta-analysis showed normal reference values of the means (effect sizes) with 95% CI of PChE, EChE, and WBChE activities of healthy adult subjects, which were 1.078 (1.015, 1.142), 1.075 (1.024, 1.125) and 1.331 (1.226, 1.436), respectively. By the subgroup analysis, heterogeneity (I2>89%) was considerably reduced in females to 4.4% and 30.1% for PChE and EChE, respectively. Funnel plots indicated no publication bias. However, Egger's regression confirmed the symmetry of the data points for PChE and WBChE activities with a significant effect on EChE. This meta-analysis showed normal reference values of PChE, EChE, and WBChE activities, measured by a modified electrometric method, in healthy adult humans.

Changes in blood oxidative stress biomarker and cholinesterase activity after general vs spinal anesthesia for elective cesarean sections

“…9,24,38 The mean PChE activities (Δ pH/20min) before anesthesia were 0.75 and 0.71 in GS and SA, respectively. These values are generally below normal ranges reported by others, 28,29 using the same electrometric method we applied in the present study. This could be related to physiological hemodynamic changes expected during pregnancy.…”

“…This enzyme is found in the liver, plasma and other tissues, and it is involved in the metabolism of some anesthetics and related muscle relaxants. 35,36 Reduced PChE activity is a biomarker of exposure to pesticides, 29,31,37 and it has been implicated in different cardiovascular and hemodynamic imbalances during anesthesia, especially at the level of the autonomic nervous system. 9,24,38 The mean PChE activities (Δ pH/20min) before anesthesia were 0.75 and 0.71 in GS and SA, respectively.…”

“…An electrometric method was used to determine PChE and EChE activities using 0.2 mL samples and 0.1 mL of 7.1% acetylcholine iodide as a substrate with a reaction time of 20 min. 28,29 The enzymatic activity was expressed as  pH/20 min.…”

In vitro Effects of Propofol and Bupivacaine on Pregnant Women’s Plasma Cholinesterase Activity and Malondialdehyde Level

“…A modified electrometric method was used to measure plasma ChE activity (∆pH/20 min at 37ºC) as described earlier using 0.2 mL plasma sample and 0.1 mL of the substrate acetylcholine iodide (7.1%) with an incubation time of 20 minutes (27,28). The plasma MDA level was measured spectrophotometrically at 535 nm, as described earlier (29).…”

“…We used the method of 10-minute incubation of the inhibitor with the ChE source (plasma) at 37ºC (30,31). The baseline and residual plasma ChE activity was measured electrometrically (27,28). The inhibitor-ChE combination (n = 5/concentration) included propofol (0-baseline, 25 and 50 µM) (22,32) and bupivacaine (0-baseline, 1.1 and 2.2 µM) (33) in the final reaction mixture (6.3 mL).…”