Factors affecting inter-individual variation in human plasma cholinesterase activity: body weight, height, sex, genetic polymorphism and age

Serum butyrylcholinesterase as a marker of COVID-19 mortality: Results of the monocentric prospective observational study

The COVID-19 pandemic represents an excessive burden on health care systems worldwide and the number of patients who require special care in the clinical setting is often hard to predict. Consequently, there is an unmet need for a reliable biomarker that could predict clinical outcomes of high-risk patients. Lower serum butyrylcholinesterase (BChE) activity was recently linked with poor outcomes of COVID-19 patients. In line with this, our monocentric observational study on hospitalized COVID-19 patients focused on changes in serum BChE activity in relation to disease progression. Blood samples from 148 adult patients of both sexes were collected during their hospital stay at the Clinics of Infectiology and Clinics of Anesthesiology and Intensive Care, Trnava University Hospital in alignment with routine blood tests. Sera were analyzed using modified Ellman's method. Patient data with information about the health status, comorbidities and other blood parameters were collected in pseudonymized form. Our results show a lower serum BChE activity together with progressive decline of BChE activity in non-survivors, while higher stable values were present in discharged or transferred patients requiring further care. Lower BChE activity was associated with higher age and lower BMI. Moreover, we observed a negative correlation of serum BChE activity with the routinely used inflammatory markers, C-reactive protein and interleukin-6. Serum BChE activity mirrored clinical outcomes of COVID-19 patients and thus serves as a novel prognostic marker in high-risk patients.

Lactiplantibacillus plantarum P9 improved gut microbial metabolites and alleviated inflammatory response in pesticide exposure cohorts

Multiple pesticide residue accumulations increase the probability of chronic metabolic diseases in humans. Thus, we applied multi-omics techniques to reveal how the gut microbiome responded to pesticide exposure. Then, we explored how probiotic Lactiplantibacillus plantarum P9 (P9) consumption impacted the gut microbiota and immune factors after high pesticide exposure. Multi-omics results indicated frequent exposure to pesticides did not alter the composition of the intestinal microbiota, but it did increase the abundance of Lipopolysaccharide in the gut, which might contribute to chronic inflammation. Supplementation with P9 maintained the homeostasis of the gut microbiota and reduced the abundance of pathogens in the high pesticide-exposed subjects. By detecting metabolites, we observed uridine and 5-oxoproline concentrations increased significantly after P9 consumption. Furthermore, P9 alleviated immune factors disorder and promoted pesticide residue excretion. Our findings provide new insights into the application of probiotics for pesticide detoxification, and suggest probiotics as daily supplements for pesticide exposure prevention.

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High-frequency pesticide exposure induced inflammatory responses to occur

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P9 maintained gut microbiota homeostasis in subjects with high pesticide exposure

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P9 significantly increased the level of beneficial metabolites in the subjects

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P9 reduced inflammatory response and promoted excretion of pesticide residues

Biomonitoring of Acetylcholinesterase (AChE) Activity among Smallholder Horticultural Farmers Occupationally Exposed to Mixtures of Pesticides in Tanzania

Biomonitoring of pesticides exposure has currently become a matter of great public concern due to the potential health effects of pesticides. This study assessed levels of acetylcholinesterase (AChE) inhibition and associated health effects in uncontrolled smallholder farming systems in rural Tanzania. A cross-sectional study was conducted of 90 exposed farmers and 61 nonexposed controls from horticultural zones. A structured questionnaire was administered, and a capillary blood sample of 10 μl was used to measure AChE activity using an Erythrocyte Acetylcholinesterase Test Mate Photometric Analyzer kit (Model 400). A multiple logistic regression model was used to investigate determinants of pesticide exposure. The study revealed that smallholder farmers are occupationally exposed to pesticides. Exposed farmers had significantly lower AChE levels. The use of personal protective equipment (PPE) did not significantly reduce the likelihood of AChE inhibition. Women, younger and older farmers, and underweight, overweight, and obese farmers were at increased risk of AChE inhibition. Increase in age (10 years) increased likelihood of AChE inhibition by 6.7%, while decrease in BMI increased likelihood of AChE inhibition by 86.7% while increased pesticides contact hours increased risk of having lower AChE at about 3 times. The number of exposure symptoms (14.10 ± 7.70) was higher in exposed farmers than unexposed. Self-reported symptoms are confirmed to correlate to lower AChE. Prevalence of tiredness (71.6% against 15.5%), fatigue (64.8% against 27.6%), soreness in joints (59.1% against 20.7%), thirst (52.3% against 12.1%), skin irritation (52.1% against 17.2%), salivation and abdominal pain (50% against 8.6% and 31.0%, respectively), muscle weakness (47.7% against 24.1%), and memory loss (47.7% against and 29.3%) differed significantly between exposed and control. This study provides useful information regarding the level of occupational and environmental exposure to pesticides in smallholder horticultural production systems. Pesticides use needs to be controlled at farm level by developing pesticides monitoring and surveillance systems.

Arylesterase phenotype-specific positive association between arylesterase activity and cholinesterase specific activity in human serum

Context: Cholinesterase (ChE) specific activity is the ratio of ChE activity to ChE mass and, as a biomarker of exposure to cholinesterase inhibitors, has a potential advantage over simple ChE activity. Objective: To examine the association of several potential correlates (serum arylesterase/paraoxonase activity, serum albumin, sex, age, month of blood collection, and smoking) with plasma ChE specific activity. Methods: We analyzed data from 195 cancer-free controls from a nested case-control study, accounting for potential confounding. Results: Arylesterase activity had an independent, statistically significant positive association with ChE specific activity, and its magnitude was the greatest for the arylesterase phenotype corresponding to the QQ PON1₁₉₂ genotype followed by phenotypes corresponding to QR and RR genotypes. Serum albumin was positively associated with ChE specific activity. Conclusions: Plasma arylesterase activity was positively associated with plasma ChE specific activity. This observation is consistent with protection conferred by a metabolic phenotype resulting in reduced internal dose.

Influence of physical exercise and gender on acetylcholinesterase and butyrylcholinesterase activity in human blood samples

The determination of cholinesterase activity in plasma and erythrocytes serves as a useful and sensitive biomarker of exposure to organophosphorus and carbamate pesticides. However, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity may be influenced by factors such as age, gender, drugs, and physical exercise. The aim of this study was to evaluate the effects of gender and physical exercise on the activity of AChE and BuChE in healthy individuals. The values for both enzymes were lower for women. Physical exercise increased the levels of BuChE, and had no significant effect on AChE. To our knowledge, this is the first clinical study evaluating the influence of physical exercise in levels of these enzymes. Considering that cholinesterase activity is a useful parameter in assessing the exposure of individuals to pesticides, it is important to understand factors that influence the determination of the enzymes in order to avoid the erroneous interpretation of results.

Association of chronic pesticide exposure with serum cholinesterase levels and pulmonary functions

The present study focused on the analysis of serum cholinesterase levels and the pulmonary function tests in seasonal farm workers who were chronically exposed to pesticides, mostly organophosphorus, in comparison with non-farm workers in the farming areas of Cukurova region, Turkey. Serum cholinesterase levels and pulmonary function tests using spyrometer in 50 male seasonal farm workers (study group) were compared to 50 male non-farm workers (control group) in this cross-sectional study. The mean serum cholinesterase enzyme level in the farm worker group (7095.5 ± 1699.4 U/L) was significantly lower than those of the control group (9716.4 ± 1484.4 U/L) (p < .001). There was no significant difference between pulmonary function tests of 2 groups (p > .05). These results show that chronic environmental organophosphorus exposure caused a decrease in the serum cholinesterase enzyme levels in farm workers, emphasizing the importance of primary prevention.

Determination of butyrylcholinesterase (BChE) phenotypes to predict the risk of prolonged apnea in persons receiving succinylcholine in the healthy population of western Iran

OBJECTIVE

The best known clinical application of serum BChE assay is to predict abnormally prolonged apnea following the application of the muscle relaxant succinylcholine. The aim of the present study was to assess the frequency of BChE phenotypes and to predict the risk of apnea for those receiving succinylcholine among the residents in western Iran.

METHODS

We examined the frequency of nine BChE phenotypes in 1548 volunteers including 816 males and 732 females with the mean age of 35+/-15 years from an apparently healthy group living in western Iran. The frequencies of BChE phenotypes were determined using BChE activity measurements and by inhibition with dibucaine, fluoride, and the compound Ro2-0683 (Hoffman-La-Roche).

RESULTS

The reference range for serum total BChE activity was 4600-14000 U/L (using butyrylthiocholine iodide as substrate). The mean value obtained for men (9030 U/L) was significantly (p<0.05) higher than that for women (8550 U/L). The frequencies of four alleles U, A, F, S were calculated to be 0.9826, 0.0165, 0.008 and 0.001, respectively. The frequency of phenotypes of BChE was as follows: normal phenotype (UU) 95.5%, moderate sensitive to succinylcholine including UA,US,UF phenotypes was 3.9% and hypersensitive to succinylcholine (AA, AF, AS, FF, SS) was 0.58%.

CONCLUSION

This study indicates that the population of western Iran has a medium frequency of succinylcholine-sensitive individuals compared to other populations. We suggest that determination of BChE activity and phenotype by the micro automated method is well suited to pre-operative screening and detection of at-risk of prolonged apnea in persons receiving succinylcholine in the healthy population of western Iran.

Blood cholinesterases as human biomarkers of organophosphorus pesticide exposure

The organophosphorus pesticides of this review were discovered in 1936 during the search for a replacement for nicotine for cockroach control. The basic biochemical characteristics of RBC AChE and BChE were determined in the 1940s. The mechanism of inhibition of both enzymes and other serine esterases was known in the 1940s and, in general, defined in the 1950s. In 1949, the death of a parathion mixer-loader dictated blood enzyme monitoring to prevent acute illness from organophosphorus pesticide intoxication. However, many of the chemical and biochemical steps for serine enzyme inhibition by OP compounds remain unknown today. The possible mechanisms of this inhibition are presented kinetically beginning with simple (by comparison) Michaelis-Menten substrate enzyme interaction kinetics. As complicated as the inhibition kinetics appear here, PBPK model kinetics will be more complex. The determination of inter- and intraindividual variation in RBC ChE and BChE was recognized early as critical knowledge for a blood esterase monitoring program. Because of the relatively constant production of RBCs, variation in RBC AChE was determined by about 1970. The source of plasma (or serum) BChE was shown to be the liver in the 1960s with the change in BChE phenotype to the donor in liver transplant patients. BChE activity was more variable than RBC AChE, and only in the 1990s have BChE individual variation questions been answered. We have reviewed the chemistry, metabolism, and toxicity of organophosphorus insecticides along with their inhibitory action toward tissue acetyl- and butyrylcholinesterases. On the basis of the review, a monitoring program for individuals mixing-loading and applying OP pesticides for commercial applicators was recommended. Approximately 41 OPs are currently registered for use by USEPA in the United States. Under agricultural working conditions, OPs primarily are absorbed through the skin. Liver P-450 isozymes catalyze the desulfurization of phosphorothioates and phosphorodithioates (e.g., parathion and azinphosmethyl, respectively) to the more toxic oxons (P = O(S to O)). In some cases, P-450 isozymes catalyze the oxidative cleavage of P-O-aryl bonds (e.g., parathion, methyl parathion, fenitrothion, and diazinon) to form inactive water-soluble alkyl phosphates and aryl leaving groups that are readily conjugated with glucuronic or sulfuric acids and excreted. In addition to the P-450 isozymes, mammalian tissues contain ('A' and 'B') esterases capable of reacting with OPs to produce hydrolysis products or phosphorylated enzymes. 'A'-esterases hydrolyze OPs (i.e., oxons), while 'B'-esterases with serine at the active center are inhibited by OPs. OPs possessing carboxylesters, such as malathion and isofenphos, are hydrolyzed by the direct action of 'B'-esterases (i.e., carboxylesterase, CaE). Metabolic pathways shown for isofenphos, parathion, and malathion define the order in which these reactions occur, while Michaelis-Menten kinetics define reaction parameters (Vmax, K(m)) for the enzymes and substrates involved, and rates of inhibition of 'B'-esterases (kis, bimolecular rate constants) by OPs and their oxons. OPs exert their insecticidal action by their ability to inhibit AChE at the cholinergic synapse, resulting in the accumulation of acetylcholine. The extent to which AChE or other 'B'-esterases are inhibited in workers is dependent upon the rate the OP pesticide is activated (i.e., oxon formation), metabolized to nontoxic products by tissue enzymes, its affinity for AChE and other 'B'-esterases, and esterase concentrations in tissues. Rapid recovery of OP BChE inhibition may be related to reactivation of inhibited forms. AChE, BChE, and CaE appear to function in vivo as scavengers, protecting workers against the inhibition of AChE at synapses. Species sensitivity to OPs varies widely and results in part from binding affinities (Ka) and rates of phosphorylation (kp) rather than rates of activation and detoxif

[Cholinesterases]

OBJECTIVE

To review current data on butyrylcholinesterase.

DATA SOURCES

Search through Medline data bases of articles in French or English.

STUDY SELECTION

Original articles and case reports were selected. Letters to editor were excluded.

DATA EXTRACTION

The articles were analyzed in order to obtain current data on biochemical structure, action, major pathological variations, especially with regard to the recent informations obtained by molecular biology concerning the identification of genetic variants.

DATA SYNTHESIS

Butyrylcholinesterase must be differentiated from acetylcholinesterase, which cannot hydrolyse succinylcholine. The physiological action of butyrylcholinesterase remains unknown, although it can hydrolyse many drugs. Excluding genetical mutations, several physiopathological situations alter butyryl-cholinesterase activity. Butyrylcholinesterase activity assessment does not allow the diagnosis of genetic variants. Whatever the origin, only deficits of more than 50% modify significantly the metabolism of succinylcholine or mivacurium. The diagnosis of a prolonged neuromuscular blockade is obtained with systematic monitoring of the neuromuscular function in case of administration of mivacurium or succinylcholine. Mivacurium should only be re-injected when one response at train of four is obtained. In case of prolonged neuromuscular blockade, the anticholinesterasic agent should not be administered when no response at train of four is obtained. The biochemical methods using inhibitors (dibucaine, fluoride) of the butyrylcholinesterase and a familial study lead to the diagnosis in most cases because the atypical and fluoride variants are the most frequent. When results are doubtful, genetic molecular methods with the use of PCR and restriction enzymes allow a rapid diagnosis.

Identification of human plasma cholinesterase variants in 6,688 individuals using biochemical analysis

In 1973, a Cholinesterase Research Unit was established in Denmark (DCRU). The primary aim was to provide a central service for determining genotypes and activity of plasma cholinesterase (BChE) in patients showing abnormal response after succinylcholine. The purpose of the present study was, on the basis of 20 years experience with this Unit, to establish accurate reference intervals for BChE activity and inhibition values for the different genotypes of BChE. Also we wanted to evaluate the influence of age and sex on the BChE activity in genotypically normal patients. Plasma cholinesterase activity was measured using benzoylcholine as substrate. The genetic variations of the enzyme were identified using differential inhibitors, i.e.: Dibucaine, Sodium Fluoride, Succinylcholine, Urea and Ro-2-0683. We investigated 6,688 patients. The reference values for the 13 genotypes represented agree with previous findings. In genotypically normal patients, no age or sex differences were found in BChE activity in children below the age of 10 years. From the age of 10 years the activity decreased significantly in both males and females, the activity in females being significantly lower than in males. In females the activity was lowest in the age group 30-40 years, returning to prepuberty level at about 60 years of age. In males the activity decreased slightly up to 50-60 years of age. Hereafter the activity was stable or tended to increase slightly. Most genotypes could be recognized using the results of the different inhibition studies. We found the inhibitors Dibucaine, Sodium fluoride, Urea and Ro-2-0683 most helpful, whereas succinylcholine was of less value.(ABSTRACT TRUNCATED AT 250 WORDS)