Pseudocholinesterase as a Biomarker for Untreated Wilson's Disease.

The aim of this study was to demonstrate that pseudocholinesterase (CHE) serum level is a useful diagnostic biomarker for untreated Wilson's disease (WD). Between 2013 and 2019, about 75 patients were referred to the outpatient department of the University of Düsseldorf with suspected Wilson's disease. In 31 patients with suspected Wilson's disease (WD-SUS-group), WD was excluded by means of investigations other than analysis of blood and urine. A total of 27 parameters of blood and urine in these 31 patients were compared to those of 20 de novo patients with manifest WD (WD-DEF-group), which parameter showed the highest significance level of difference between the WD-DEF-group and the WD-SUS-group. Thereafter, receiver operating characteristics (ROC-curves) were analyzed to evaluate which parameter showed the largest area under the curve (AUC) to detect WD. Finally, a logistic regression analysis was performed to analyze which combination of parameters allowed the best classification of the 51 patients either into the WD-DEF-group or into the WD-SUS-group. CHE showed the highest significance level for a difference between the WD-DEF- and WD-SUS-group, had the highest AUC, and, in combination with ceruloplasmin, allowed 100% correct classification. Without CHE, no other combination of parameters reached this level of correct classification. After the initiation of treatment, which regularly results in an improvement in CHE, the high diagnostic accuracy of this biomarker was lost. Cholinesterase turns out to be an excellent biomarker for differentiation between untreated de novo patients with manifest WD and heterozygotic gene carriers.

Pesticide toxicity assessment and geographic information system (GIS) application in small-scale rice farming operations, Thailand.

The objectives of the study were to evaluate the impact of pesticide exposure on farmer health during non-active rice farming and active rice farming periods and present the change in the individual cholinesterase activities (%reduction) on the geographic information system (GIS) mapping in Nakhon Ratchasima Province, Thailand. Acetyl- and butyryl-cholinesterase (AChE and BuChE) activities were monitored during both study periods using Test-mate ChE (Model 400). The location of paddy fields was specified using Garmin geographic positioning system MAP 62s. Fifty-eight farmers who participated in this study had an average age of 49.2 ± 6.9 years. Higher prevalence of all health symptoms was observed among farmer participants during the active rice farming period comparing to the non-active rice farming period (p < 0.01). Furthermore, farmers had significantly lower activities of AChE and BuChE during the active rice farming period comparing to the non-active rice farming period (p < 0.01). Our findings indicate that the GIS mapping indicate that the cases with a significant enzyme inhibition have dispersed across the agricultural and the nearby residential areas. This, investigation can be used to promote safer use of pesticides among farmers and mitigate pesticide exposure among residents living in close proximity to a rice field.

Point-of-care testing of butyrylcholinesterase activity through modulating the photothermal effect of cuprous oxide nanoparticles.

Butyrylcholinesterase (BChE) is an important indicator for clinical diagnosis of liver dysfunction, organophosphate toxicity, and poststroke dementia. Point-of-care testing (POCT) of BChE activity is still a challenge, which is a critical requirement for the modern clinical diagnose. A portable photothermal BChE assay is proposed through modulating the photothermal effects of Cu2O nanoparticles. BChE can catalyze the decomposition of butyrylcholine, producing thiocholine, which further reduce and coordinate with CuO on surface of Cu2O nanoparticle. This leads to higher efficiency of formation of Cu9S8 nanoparticles, through the reaction between Cu2O nanoparticle and NaHS, together with the promotion of photothermal conversion efficiency from 3.1 to 59.0%, under the excitation of 1064 nm laser radiation. An excellent linear relationship between the temperature change and the logarithm of BChE concentration is obtained in the range 1.0 to 7.5 U/mL, with a limit of detection of 0.076 U/mL. In addition, the portable photothermal assay shows strong detection robustness, which endows the accurate detection of BChE in human serum, together with the screening and quantification of organophosphorus pesticides. Such a simple, sensitive, and robust assay shows great potential for the applications to clinical BChE detection and brings a new horizon for the development of temperature based POCT.

Cholinesterase activity in serum during general anesthesia in patients with or without vascular disease.

Maintaining hemodynamic stability during the induction and maintenance of anesthesia is one of the challenges of the anesthesiologist. Patients with vascular disease are at increased risk of instability due to imbalance between the sympathetic and parasympathetic parts of the autonomic nervous system, a balance accessible by serum cholinesterase activity. We aim to characterize the dynamics of cholinesterase activity in patients undergoing general anesthesia (GA) and surgery. This was a prospective study of 57 patients undergoing ambulatory or vascular surgery under GA. Cholinesterase activity was measured before the induction of anesthesia, after 15 min and at the end of surgery by calculating the capacity of serum acetylcholinesterase (AChE) and butyrylcholinesterase to hydrolyze AcetylThioCholine. Data on atherosclerotic disease, anesthesia management were analyzed. Both AChE and total cholinergic status (CS) decreased significantly after GA induction at 15 min and even more so by the end of surgery. Vascular surgery patients had lower baseline cholinesterase activity compared to ambulatory surgery patients. Patients requiring intraoperative administration of phenylephrine for hemodynamic support (21.1%) had a significantly lower level of AChE and CS compared to untreated patients. Our findings serve as a mirror to the sympathetic/parasympathetic imbalance during GA, with a marked decrease in the parasympathetic tone. The data of a subgroup analysis show a correlation between low cholinesterase activity and an increase in the need for hemodynamic support.

Identification and Study of Biomarkers from Novichok-Inhibited Butyrylcholinesterase in Human Plasma.

To identify biomarkers of ethyl (1-(diethylamino)ethylidene)phosphoramidofluoridate (A234)- or methyl (1-(diethylamino)ethylidene)phosphoramidofluoridate (A232)-inhibited butyrylcholinesterase (BChE), we investigated nonapeptide adducts containing the active site serine, which plays a key role in enzyme activity, using LC-MS/HRMS. Biomarkers were acquired as expected, and they exhibited a significant amount of fragment ions from the inhibiting agent itself, in contrast to the MS2 spectra of conventional nerve agents. These biomarkers had a higher abundance of [M+2H]2+ ions than [M+H]+ ions, making doubly charged ions more suitable for trace analysis.

Reactivation of organophosphate-inhibited serum butyrylcholinesterase by novel substituted phenoxyalkyl pyridinium oximes and traditional oximes.

Organophosphorus compounds (OPs) include nerve agents and insecticides that potently inhibit acetylcholinesterase (AChE), an essential enzyme found throughout the nervous system. High exposure levels to OPs lead to seizures, cardiac arrest, and death if left untreated. Oximes are a critical piece to the therapeutic regimen which remove the OP from the inhibited AChE and restore normal cholinergic function. The current oximes 2-PAM, MMB-4, TMB-4, HI-6, and obidoxime (OBD) have two drawbacks: lack of broad spectrum protection against multiple OP structures and poor brain penetration to protect against OP central neurotoxicity. An alternative strategy to enhance therapy is reactivation of serum butyrylcholinesterase (BChE). BChE is stoichiometrically inhibited by OPs with no apparent toxic result. Inhibition of BChE in the serum followed by reactivation could create a pseudo-catalytic scavenger allowing numerous regenerations of BChE to detoxify circulating OP molecules before they can reach target AChE. BChE in serum from rats, guinea pigs or humans was screened for the reactivation potential of our novel substituted phenoxyalkyl pyridinium oximes, plus 2-PAM, MMB-4, TMB-4, HI-6, and OBD (100µM) in vitro after inhibition by highly relevant surrogates of sarin, VX, and cyclosarin, and also DFP, and the insecticidal active metabolites paraoxon, phorate-oxon, and phorate-oxon sulfoxide. Novel oxime 15 demonstrated significant broad spectrum reactivation of OP-inhibited rat serum BChE while novel oxime 20 demonstrated significant broad spectrum reactivation of OP-inhibited human serum BChE. All tested oximes were poor reactivators of OP-inhibited guinea pig serum BChE. The bis-pyridinium oximes were poor BChE reactivators overall. BChE reactivation may be an additional mechanism to attenuate OP toxicity and contribute to therapeutic efficacy.

Effect of pesticide exposure on total antioxidant capacity and biochemical parameters in Brazilian soybean farmers.

Farmers represent a population highly vulnerable to the toxic effects of pesticide exposure. Antioxidant capacity and biochemical parameters have been used as biomarkers of occupational exposure to pesticides. The aim of this study was to evaluate hepatic and renal parameters as well as butyrylcholinesterase (BChE) activity and ferric-reducing ability of plasma (FRAP) considering high and low exposure periods in soybean farmers in southern Brazil. The exposed group consisted of 50 soybean farmers. Two control groups were used, composed by 35 (Novo Hamburgo control group) and 28 (Sertão control group) subjects not exposed to pesticides. Farmers blood samples were collected during the high and low pesticide exposure periods. BChE, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), urea, and creatinine levels were determined. The FRAP assay was carried out to evaluate the antioxidant potential in the exposed group. Considering the exposed group, significantly lower BChE and increased AST activity were observed during high pesticide exposure period as well as higher FRAP, urea and creatinine levels; however, ALT and GGT did not differ between the two periods. When compared with the control groups, only urea and creatinine were higher in the exposed group. The present results indicate that occupational exposure to mixtures of pesticides might elicit adverse effects at the biochemical level. In addition, the study highlights the importance in considering periods of a same crop season with different degree of pesticide exposure during biologic monitoring of these biochemical parameters.

Chemical composition, in vitro antioxidant, anticholinesterase and antibacterial activities of Linaria scariosa Desf.

The study was performed on the dichloromethane (DCM), ethyl acetate (EAc) and n-butanol (Bu) fractions (F) obtained from the 80% ethanol extract of Linaria scariosa Desf. aerial parts, collected in the North Eastern region of Algeria. Remarkable total phenolic and flavonoid contents were obtained, mainly for EAcF. These results were in accordance with the antioxidant activity of EAcF against DPPH, ABTS, CUPRAC and reducing power tests. DCMF and BuF exhibited significant cholinesterase activity inhibition of BChE and AChE. Moreover, EAcF displayed only moderate antibacterial activities, especially against S. aureus. The biological results were correlated to the chemical components, deduced by both GC-MS analysis of the fractions and the isolation of hemipholin, pectolinarigenin, antirride, antirrinoside, pectolinarin and linariosise, some of which known to exhibit potent effects on the tested biological activities. The study provides the first biological and chemical investigation on Linaria scariosa Desf (unresolved name).

Nondestructive biomarkers in giant toad (Rhinella marina) to assess the effect of complex mixture of pollutants in Coatzacoalcos River, Mexico.

In this study, we evaluated the usefulness of nondestructive biomarkers approach in giant toads (Rhinella marina). We obtained blood samples and the residual condition index of toads from rural and industrial zones from Coatzacoalcos River, Mexico (COA). In the blood samples, we determined the activity of enzymes, lipid peroxidation, and the presence of cell death (apoptosis). We found that the activity of the enzyme delta-aminolevulinic dehydratase was lower. Still, the glutathione s-transferase activity and the percentage of apoptosis in erythrocytes were higher in the toads of COA than laboratory toads. Meanwhile, some biomarkers in toads showed differences when compared between Industrial and Rural zones. These results and correlations between biomarkers showed how the response changed in the toads living near the industrial zones. We demonstrate that a nondestructive biomarkers approach can be useful in environmental studies with anuran amphibians.

Effects of low-level imidacloprid oral exposure on cholinesterase activity, oxidative stress responses, and primary DNA damage in the blood and brain of male Wistar rats.

Imidacloprid is a neonicotinoid insecticide that acts selectively as an agonist on insect nicotinic acetylcholine receptors. It is used for crop protection worldwide, as well as for non-agricultural uses. Imidacloprid systemic accumulation in food is an important source of imidacloprid exposure. Due to the undisputable need for investigations of imidacloprid toxicity in non-target species, we evaluated the effects of a 28-day oral exposure to low doses of imidacloprid (0.06 mg/kg b. w./day, 0.8 mg/kg b. w./day and 2.25 mg/kg b. w./day) on cholinesterase activity, oxidative stress responses and primary DNA damage in the blood and brain tissue of male Wistar rats. Exposure to imidacloprid did not cause significant changes in total cholinesterase, acetylcholinesterase and butyrylcholinesterase activities in plasma and brain tissue. Reactive oxygen species levels and lipid peroxidation increased significantly in the plasma of rats treated with the lowest dose of imidacloprid. Activities of glutathione-peroxidase in plasma and brain and superoxide dismutase in erythrocytes increased significantly at the highest applied dose. High performance liquid chromatography with UV diode array detector revealed the presence of imidacloprid in the plasma of all the treated animals and in the brain of the animals treated with the two higher doses. The alkaline comet assay results showed significant peripheral blood leukocyte damage at the lowest dose of imidacloprid and dose-dependent brain cell DNA damage. Oral 28-day exposure to low doses of imidacloprid in rats resulted in detectable levels of imidacloprid in plasma and brain tissue that directly induced DNA damage, particularly in brain tissue, with slight changes in plasma oxidative stress parameters.

Butyrylcholinesterase: An economical marker of disease activity in oral squamous cell carcinoma before and after therapy.

INTRODUCTION: Biomarkers which can predict disease progression and serve as prognostic indicators are necessary for better management of oral cancer. Studies have shown that Cholinesterase plays an important role in cellular proliferation, differentiation and may have a possible involvement in tumor growth. AIM AND OBJECTIVE: The present study is aimed to determine the utility of serum Butyrylcholinesterase (BChe) levels as a marker for progression of oral squamous cell carcinoma (OSCC) in relation to the grade of the tumor and to determine if any variation occurred in the levels of BChe before and after therapy. MATERIALS AND METHODS: A total of 120 patients were included in the study and divided into two groups as Group A-30 patients (healthy individuals) and Group B-90 cases of histopathologically diagnosed OSCC. The blood sample was collected before surgery, re-collected after the completion of radiotherapy (i.e., 3 and 6 months postsurgery) and analyzed biochemically for the concentration of BCh. STATISTICAL ANALYSIS: Paired t-test, ANOVA, and post hoc test (Bonferroni) were used for determining the statistical significance. RESULTS: BChe levels were lower in OSCC (2940.32-1405.50 u/l when compared with controls (11149.60-11243.07 unit/l) and this difference was statistically significant. Postoperatively at 3 months, the serum BChe levels of OSCC patients increased almost two-fold compared to the preoperative values, and this difference was also statistically significant (P = 0.000) After 6 months, these levels further increased but did not reach those of controls. CONCLUSION: BChe can be used as an inexpensive, easy to use, noninvasive biomarker for the evaluation of disease-free survival in OSCC patients.

In Situ Generation of Prussian Blue by MIL-53 (Fe) for Point-of-Care Testing of Butyrylcholinesterase Activity Using a Portable High-Throughput Photothermal Device.

Butyrylcholinesterase (BuChE), the primary source of serum cholinesterase activity, is an indispensable biochemical marker for clinical diagnosis of liver function and organophosphorus poisoning. The requirement for bulky and expensive instruments represents a huge hindrance for point-of-care testing (POCT) of BuChE, especially in resource-limited settings. Herein, an easy-operated, economic, and portable photothermal (PT) biosensing platform for high-throughput BuChE detection was rationally designed. BuChE could "light up" the PT signal through in situ generation of Prussian blue (PB) by MIL-53 (Fe), which allowed us to translate biological signals into temperature signals. Such temperature change signals could be monitored at high throughput (six samples for a single measurement) by a miniature self-made integrated PT device via combining separable 96-well plates, a three-dimensional (3D) printed sample bracket, 808 nm lasers, and thermometers, satisfying the requirement for rapid on-site detection in a large batch with low cost. In addition, the large specific surface area, 3D network structure, and high porosity of MIL-53 (Fe) offered a beneficial platform for its reaction with enzymatic hydrolysate, resulting in high sensing sensitivity and low detection limit (0.3 U L-1), which was at least 20 000 times lower than the normal human serum BuChE activity. This facile, affordable, and broad applicability PT sensing platform provides a beneficial reference for the rational design of other disease diagnostic approaches suitable for POCT.

Monoclonal antibodies to fetal bovine serum acetylcholinesterase distinguish between acetylcholinesterases from ruminant and non-ruminant species.

Two types of cholinesterases (ChEs) are present in mammalian blood and tissues: acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). While AChE regulates neurotransmission by hydrolyzing acetylcholine at the postsynaptic membranes and neuromuscular junctions, BChE in plasma has been suggested to be involved in detoxifying toxic compounds. This study was undertaken to establish the identity of circulating ChE activity in plasmas from domestic animals (bovine, ovine, caprine, porcine and equine) by assessing sensitivity to AChE-specific inhibitors (BW284c51 and edrophonium) and BChE-specific inhibitors (dibucaine, ethopropazine and Iso-OMPA) as well as binding to anti-FBS AChE monoclonal antibodies (MAbs). Based on the inhibition of ChE activity by ChE-specific inhibitors, it was determined that bovine, ovine and caprine plasma predominantly contain AChE, while porcine and equine plasma contain BChE. Three of the anti-FBS AChE MAbs, 4E5, 5E8 and 6H9, inhibited 85-98% of enzyme activity in bovine, ovine and caprine plasma, confirming that the esterase in these plasmas was AChE. These MAbs did not bind to purified recombinant human or mouse AChE, demonstrating that these MAbs were specific for AChEs from ruminant species. These MAbs did not inhibit the activity of purified human BChE, or ChE activity in porcine and equine plasma, confirming that the ChE in these plasmas was BChE. Taken together, these results demonstrate that anti-FBS AChE MAbs can serve as useful tools for distinguishing between AChEs from ruminant and non-ruminant species and BChEs.

Novel "turn on-off" paper sensor based on nonionic conjugated polythiophene-coated CdTe QDs for efficient visual detection of cholinesterase activity.

An increasing number of patients are living with Alzheimer's disease (AD); thus, the need for a method to detect AD early and sensitively has become urgent, and the demand for an intelligent analytical platform is growing year by year. Abnormal levels of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are known to be indicative of AD. In this work, a novel conjugated polythiophene (CP) compound was successfully combined with CdTe quantum dots (QDs) to improve their selectivity and sensitivity. The QDs successfully enabled the detection of low concentrations of AChE by turning on the fluorescence of the CdTe/CP via the interaction between CP and thiocholine produced by ATCh hydrolysis and aggregation induced emission enhancement (AIEE). Under optimal conditions, we reached a low detection limit of 0.14 U L-1, which is 7.9 times lower than that of pristine QDs. More importantly, an efficient, inexpensive, and disposable paper-based platform, which allows the efficient visual detection of AChE activity via the color variation of CdTe/CP, was designed. Moreover, the accuracy of the method was demonstrated by conducting a recovery test in human serum, in which the recoveries reached 107% and 110%, proving that CdTe/CP has considerable potential to be used for analyzing real biological samples. The advantages of this method are its simplicity, fast detection capability, affordability, and the fact that it can be used for on-site detection of AChE activity. Furthermore, it has certain guiding significance for detecting AD.

A case report of cholinesterase inhibitor poisoning: cholinesterase activities and analytical methods for diagnosis and clinical decision making.

Suicidal ingestion of organophosphorus (OP) or carbamate (CM) compounds challenges health care systems worldwide, particularly in Southeast Asia. The diagnosis and treatment of OP or CM poisoning is traditionally based on the clinical appearance of the typical cholinergic toxidrome, e.g. miosis, salivation and bradycardia. Yet, clinical signs might be inconclusive or even misleading. A current case report highlights the importance of enzymatic assays to provide rapid information and support clinicians in diagnosis and rational clinical decision making. Furthermore, the differentiation between OP and CM poisoning seems important, as an oxime therapy will most probably not provide benefit in CM poisoning, but-as every pharmaceutical product-it might result in adverse effects. The early identification of the causing agent and the amount taken up in the body are helpful in planning of the therapeutic regimen including experimental strategies, e.g. the use of human blood products to facilitate scavenging of the toxic agent. Furthermore, the analysis of biotransformation products and antidote levels provides additional insights into the pathophysiology of OP or CM poisoning. In conclusion, cholinesterase activities and modern analytical methods help to provide a more effective treatment and a thorough understanding of individual cases of OP or CM poisoning.

Magnitude of behavioral deficits varies with job-related chlorpyrifos exposure levels among Egyptian pesticide workers.

Chronic occupational exposure to organophosphorus pesticides (OPs) is consistently associated with deficits on behavioral tests when compared to unexposed comparison groups. However, a dose-response relationship has yet to be established, leading some to doubt an association between occupational OP exposure and behavioral deficits. Pesticide application teams in Egypt who are primarily exposed to one OP, chlorpyrifos (CPF), were recruited into a field assessment. Trail Making A and the more challenging Trail Making B tests were administered to 54 engineers (who supervise the pesticide application process, usually from the side of the field), 59 technicians (who guide the pesticide applicators in the field), 31 applicators (who mix and apply pesticides using knapsack sprayers), and 150 controls (who did not work in the fields) at two different times during the OP application season as well as immediately after applications had ended and 1.5 months later. All participants were males since only males work on pesticide application teams in Egypt. Urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific metabolite of CPF, confirmed the pattern of lower to higher CPF exposures from engineers to technicians to applicators, and these were all greater than urinary metabolite levels in controls. A consistent relationship between job title and performance speed on the behavioral task was observed: Controls had the best (fastest) performance on Trail Making A and B tests throughout the application season, and applicators had significantly slower performance than engineers on Trail Making A (p = 0.015) and B (p = 0.003). However, individual urinary TCPy, blood acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) levels did not predict individual performance. This study identifies a dose-related effect based on job title, which serves as a surrogate for chronic exposure in that differing job titles exhibit varying group exposure levels. The results establish that chronic occupational exposure to chlorpyrifos is neurotoxic and suggest that the classic biomarkers of recent CPF exposure are not predictive of chronic exposure effects.

Correlation of plasma butyrylcholinesterase concentration with Acethylcholinesterase H353N polymorphism in the inflammatory response of Chagas disease patients.

Trypanosoma cruzi infection triggers an intense production of pro-inflammatory cytokines mediated by T helper 1 lymphocytes, inducing the anti-inflammatory reflex of acetylcholine (ACh). The ACh concentration modulation is associated to the two major esterases, the acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). AChE H353N protein polymorphism is related to low Chagas chronic disease prognostic. In order to evaluate the correlation of plasmatic BuChE concentration and the presence of AChE H353N polymorphism in Chagas disease patients and healthy individuals, we studied two groups of individuals, one of 61 Chagas disease patients and another of 74 healthy individuals. Plasma concentration of BuChE was measured by the chemiluminescent method and AChE H353N polymorphism was investigated by PCR-RFLP and sequencing of the respective encoding AChE gene fragment. The BuChE concentration was statistically higher in Chagas disease patients, with no AChE genotype significant influence. AChE genotypes YT*A/YT*A, YT*A/YT*B and YT*B/YT*B, respectively, were expressed in 53 (86.88%), 7 (11.46%) and one (1.64%) chagasic patients, and in 68 (91.89%), 6 (8.10%) and none healthy individuals. BuChE activity may represent an important marker for chronic Chagas disease inflammatory process and prognostic. Lower BuChE concentration correlated with AChE YT*B allele, although without statistical power.

Cholinesterase alterations in delirium after cardiosurgery: a German monocentric prospective study.

OBJECTIVES: Postoperative delirium (POD) is a common complication after elective cardiac surgery. Recent evidence indicates that a disruption in the normal activity of the cholinergic system may be associated with delirium. DESIGN: Prospective observational study. SETTING: Single-centre at a European academic hospital. PRIMARY AND SECONDARY OUTCOME MEASURES: In our study the enzyme activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were determined preoperatively as well as on the first and second postoperative day. The confusion assessment method for the intensive care unit was used to screen patients for the presence of POD. RESULTS: A total of 114 patients were included in the study. POD was associated with a decrease in BChE activity on postoperative day 1 (p=0.03). In addition, patients who developed POD, had significantly lower preoperative AChE activity than patients without POD (p<0.01). Multivariate analysis identified a preoperatively decreased AChE activity (OR 3.1; 95% CI 1.14 to 8.46), anticholinergic treatment (OR 5.09; 95% CI 1.51 to 17.23), elevated European System for Cardiac Operative Risk Evaluation (OR 3.68; 95% CI 1.04 to 12.99) and age (OR 3.02; 95% CI 1.06 to 8.62) to be independently associated with the development of POD. CONCLUSIONS: We conclude that a reduction in the acetylcholine hydrolysing enzyme activity in patients undergoing cardiac surgery may correlate with the development of POD.

Butyrylcholinesterase, a stereospecific in vivo bioscavenger against nerve agent intoxication.

Human butyrylcholinesterase (E.C. 3.1.1.8) purified from blood plasma has previously been shown to provide protection against up to five and a half times the median lethal dose of an organophosphorus nerve agent in several animal models. In this study the stoichiometric nature of the protection afforded by human butyrylcholinesterase against organophosphorus nerve agents was investigated in guinea pigs. Animals were administered human butyrylcholinesterase (26.15 mg/kg ≡ 308 nmol/kg) by the intravascular or intramuscular route. Animals were subsequently dosed with either soman or VX in accordance with a stage-wise adaptive dose design to estimate the modified median lethal dose in treated animals. Human butyrylcholinesterase (308 nmol/kg) increased the median lethal dose of soman from 154 nmol/kg to 770 nmol/kg. Comparing the molar ratio of agent molecules to enzyme active sites yielded a stoichiometric protective ratio of 2:1 for soman, likely related to the similar stereoselectivity the enzyme has compared to the toxic target, acetylcholinesterase. In contrast, human butyrylcholinesterase (308 nmol/kg) increased the median lethal dose of VX from 30 nmol/kg to 312 nmol/kg, resulting in a stoichiometric protective ratio of only 1:1, suggesting a lack of stereoselectivity for this agent.

The impact of sialylation linkage-type on the pharmacokinetics of recombinant butyrylcholinesterases.

Chinese hamster ovary (CHO) cells typically produce glycoproteins with N-glycans terminating in α-2,3 sialylation. Human cells produce glycoproteins that include α-2,3 and α-2,6 sialic acids. To examine the impact of altering protein sialylation on pharmacokinetic properties, recombinant human butyrylcholinesterase (BChE) was produced in CHO cells by knocking out the α-2,3 sialyltransferase genes followed by overexpression of the α-2,6 sialyltransferase (26BChE) enzyme. The N-glycan composition of 26BChE was compared to BChE with α-2,3 sialylation (23BChE) derived from wild-type CHO cells. Both 23BChE and 26BChE exhibited comparable antennarity distributions with bi-antennary di-sialylated glycans representing the most abundant glycoform. CD-1 mice were intravenously injected with the 23BChE or 26BChE, and residual BChE activities from blood collected at various time points for pharmacokinetic analyses. Although 23BChE contained a slightly lower initial sialylation level compared to 26BChE, the molecule exhibited higher residual activity between 5 and 24 hr postinjection. Pharmacokinetic analyses indicated that 23BChE exhibited an increase in area under the curve and a lower volume of distribution at steady state than that of 26BChE. These findings suggest that the type of sialylation linkage may play a significant role in the pharmacokinetic behavior of a biotherapeutic when tested in in vivo animal models.