Depressive symptoms and suicide attempts among farmers exposed to pesticides.

Pesticides safeguard crop health but may diminish cholinesterase activity in farmers, potentially leading to psychiatric disorders like depression and suicide attempts. This study, with 453 participants (225 pesticide-exposed farmers, 228 non-farmers) in Almería, Spain, aimed to investigate the presence of depressive symptoms and suicide attempts, the decrease acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity, and their relationship with pesticide exposure in farmers. Depressive symptoms were evaluated using the Spanish adaptation of the Beck Depression Inventory, and blood samples were analyzed for AChE and BChE activity. Farmers showed significantly increased risk of moderate/severe depression and suicide attempts compared to non-farmers (OR = 2.18; p = 0.001), with highest risks observed among mancozeb users (OR = 2.76; p = 0.001 for depression) and malathion users (OR = 3.50; p = 0.001 for suicide attempts). Findings emphasize elevated depression and suicide risks among pesticide-exposed farmers, particularly associated with chlorpyrifos, mancozeb, and malathion exposure.

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.

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.

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.

Gold Nanoclusters/Iron Oxyhydroxide Platform for Ultrasensitive Detection of Butyrylcholinesterase.

The combination of gold nanoclusters (AuNCs) and nanomaterial-based quencher creates an innovative method for sensors design. In this work, we report a fluorescent sensing platform for sensitive detection of butyrylcholinesterase (BChE). The fluorescence of AuNCs can be quenched by iron oxyhydroxide (FeOOH) nanomaterials. In the presence of BChE and acetylthiocholine (ATCh), nano-FeOOH can be effectively decomposed by the enzymatic hydrolysate (thiocholine), leading to the recovery of AuNCs fluorescence. The Au/FeOOH exhibits the highest fluorescence quenching efficiency compared with other transition metal oxyhydroxide-based sensing systems, e.g., Au/CoOOH and Au/NiOOH. The corresponding fluorescence recovery efficiency is also the best for Au/FeOOH. The large surface area of nanomaterials and thin nanostructure provide a favorable platform for the reaction of enzymatic hydrolysate and eventually improve the high sensitivity of the probe. A linear detection range for BChE is achieved within 5-100 ng mL-1 along with a detection limit of 4 ng mL-1. By taking advantage of the high sensitivity, the Au/FeOOH was successfully used for BChE quantification in 2 µL of finger blood.

A Simple 3D-Printed Enzyme Reactor Paper Spray Mass Spectrometry Platform for Detecting BuChE Activity in Human Serum.

To achieve personalized healthcare, a quick, accurate, and high-throughput method to detect disease biomarkers is essential. In the traditional practice, mass spectrometry is one of the most powerful tools and is widely studied. However, the test of human serum usually requires complicated sample pretreatment, tedious operations, and precise condition control, especially for the detection of enzymes as biomarkers. As butyrylcholinesterase (BuChE) has an indicative significance in detecting degenerative disease, liver injury, and organophosphate poisoning, the quick quantification of BuChE is of vital importance to the clinic. In this paper, we report the design and fabrication of a portable 3D-printed enzyme reactor paper spray cartridge (3D ER-PS) with integrated functions: temperature control, enzyme reaction, analyte transfer, and paper spray ionization. Coupled with mass spectrometry, quantitative testing of BuChE activity in human serum was realized conveniently and accurately. While it only requires very simple sample preparation, the results from current 3D ER-PS approach are well consistent with those obtained using Ellman's method. This 3D ER-PS platform not only provides a novel solution for the liquid biopsy of BuChE in clinics but also contributes to the development of quick and targeted medical approaches for analyzing other types of serum biomarker molecules in the field of disease diagnosis.

In vitro and in silico analysis of novel astaxanthin-s-allyl cysteine as an inhibitor of butyrylcholinesterase and various globular forms of acetylcholinesterases.

In Alzheimer's disease (AD) and diabetes-associated cognitive decline, the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity is increased. AChE exists as different globular molecular forms: tetramer (G4), dimer (G2) and monomer (G1). In adult brain, G4 form is abundant however in AD, the ratio of lower molecular forms (G1) to G4 form increased. Hence, the present study delineated the inhibition of novel astaxanthin-s-allyl cysteine (AST-SAC) against BChE and various molecular forms of AChE. Cobra venom, human erythrocyte and Electrophorus electricus was used as source of G1, G2 and G4 form of AChE. AST-SAC showed inhibition against G1 (IC50 = 0.72 µM, competitive, Ki = 0.66 µM), G2 (IC50 = 0.65 µM, mixed, Ki = 0.50 µM) and G4 (IC50 = 0.67 µM, competitive, Ki = 0.67 µM) form of AChE. AST-SAC inhibited human brain AChE (IC50 = 0.84 µM, competitive, Ki = 0.53 µM) and human serum BChE (IC50 = 0.80 µM, competitive, Ki = 0.58 µM). In silico analysis revealed the interaction of AST-SAC with the amino acids present in peripheral anionic and catalytic site of human AChE and BChE. Molecular dynamics simulation confirmed the stable interaction of AST-SAC in the active site gorge of AChE and BChE.

The role of ghrelin and tumor necrosis factor alpha in diazinon-induced dyslipidemia: insights into energy balance regulation.

The evidence shows that organophosphate compounds (OPCs), as toxic agents that stimulate the cholinergic system, can increase the incidence of metabolic disorders such as dyslipidemia. In the present study, we focused on the role of tumor necrosis factor alpha (TNF-α) and serum leptin and ghrelin in Diazinon (DZN)-induced dyslipidemia. The rats were randomly divided into five groups comprising eight animals, and all were treated via oral gavage for 28 consecutive days as follows: group one received only corn oil daily, while groups two through five received different doses of DZN dissolved in corn oil equal to 1/40, 1/20, 1/10 and 1/5 of the LD50 daily, respectively. The alteration of the serum lipid profile, such as triglycerides, high-density lipoprotein (HDL) and very-low-density lipoprotein (VLDL), was confirmed the occurrence of dyslipidemia in the range of doses 1/20-1/5 LD50 of DZN. Although no changes were found in the serum leptin levels, a significant increase was observed in the size of adipocytes, as well as in the TNF-α and ghrelin serum levels, and in the accumulation of epididymal fat, especially at a dose of 1/5 LD50 of DZN. It seems that interactions among the inflammatory reaction, cholinergic pathways and ghrelin secretion may be effective causes of DZN-induced dyslipidemia.

Oxidative and histopathological alterations after sub-acute exposure of diisopropyl phosphorofluoridate in mice: Beneficial effect of N­acetylcysteine.

AIMS: Protective efficacy of N­acetylcysteine (NAC) was assessed against sub-acute diisopropyl phosphorofluoridate (DFP) poisoning in mice. MAIN METHODS: Mice were allocated into nine groups of six each: vehicle control; DFP (0.125 LD50 ≈ 0.483 mg/kg bwt, s.c.); DFP + Atropine (ATR, 10 mg/kg bwt, i.p., 0 min); DFP + Pralidoxime (2-PAM, 30 mg/kg bwt, i.m., 0 min); DFP + NAC (150 mg/kg bwt, i.p., -60 min); DFP + ATR + NAC; DFP + 2-PAM + NAC; DFP + ATR + 2-PAM; and DFP + ATR + 2-PAM + NAC. Animals received various treatments for 21 d daily. Plasma butyrylcholinesterase (BChE) was measured after 7, 14 and 21 d of exposure. Brain acetylcholinesterase (AChE) and reduced glutathione (GSH), malondialdehyde (MDA), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and superoxide dismutase (SOD) were measured (brain, liver and kidney) after 21 d of exposure. Histopathology, immunohistochemistry, and Western blot for inducible nitric oxide synthase (iNOS) and c-fos were also performed. KEY FINDINGS: DFP significantly reduced BChE and AChE levels. Diminished GSH, CAT, SOD (brain and liver), GPx, GR, and elevated MDA (Brain) levels were also observed. DFP caused notable histopathology (brain, liver and kidney) and over expression of iNOS, and c-fos proteins (brain). NAC enhanced the protective efficacy of ATR and 2-PAM in most parameters, without any appreciable protection in iNOS and c-fos expression. SIGNIFICANCE: NAC as an adjunct with ATR and 2-PAM, exhibited marked beneficial effects against sub-acute DFP poisoning, indicating its possible implications in the management of OP poisoning.

Oxidative stress linked to changes of cholinesterase and adenosine deaminase activities in experimentally infected chicken chicks with Eimeria spp.

Both oxidative stress and alterations in adenosinergic and cholinergic systems participate in initiation and progression of parasitic infectious diseases. Nevertheless, the involvement of these pathways during eimeriosis remains poorly understood. Therefore, the aim of this study was to evaluate the involvement of adenosinergic and cholinergic systems in regulation of inflammatory response and oxidative stress in chicken chicks experimentally infected with Eimeria spp. Two groups were formed for comparison at 3 time points (days 5, 10 and 15) of infection (PI): uninfected (control) and infected. Erythrocyte counts, hematocrit and hemoglobin levels were lower in infected chicks on day 15 post-infection (PI). Total leukocytes, heterophil and lymphocyte counts were higher in infected chicks on days 5 and 10 PI, while eosinophil counts were higher only on day 10 PI. Serum levels of total protein and globulins were higher in infected chicks on days 10 and 15 PI, while triglycerides and cholesterol levels were lower on day 15 PI. Acetylcholinesterase activity in total blood and butyrylcholinesterase activity in serum were higher in infected chicks on day 15 PI, while adenosine deaminase activity was higher on day 10 PI and lower on day 15 PI compared with the respective control. Finally, serum levels of reactive oxygen species and catalase activity in total blood were higher in infected chicks on day 15 PI, while superoxide dismutase activity in total blood was lower at the same time of infection. These data suggest that cholinergic and adenosinergic systems display a pro-inflammatory profile that contributes to impairment of immune and inflammatory responses in a mixed Eimeria infection. Furthermore, oxidative stress may contribute to clinical signs of disease as well as to pathogenesis. In summary, the impairment of immune response and alterations in blood antioxidant/oxidant status contributes to disease pathophysiology.

The value of pretreatment serum butyrylcholinesterase level as a novel prognostic biomarker in patients with cervical cancer treated with primary (chemo-)radiation therapy.

BACKGROUND: Deficiency in butyrylcholinesterase (BChE), a condition commonly noticed in liver damage, inflammation, and malnutrition, has previously been associated with impaired prognosis in different malignancies. The aim of the present study was to investigate the value of pretreatment serum BChE levels as a prognostic biomarker in patients with cervical cancer treated with primary (chemotherapy-[chemo-])radiation therapy. METHODS: We retrospectively evaluated data of a consecutive series of patients with cervical cancer treated with primary (chemo-)radiation therapy between 1998 and 2015. Pretreatment serum BChE levels were correlated with clinico-pathological parameters and response to treatment. Uni- and multivariate survival analyses were performed to assess the association between decreased serum BChE levels and progression-free (PFS), cancer-specific (CSS), and overall survival (OS). RESULTS: A total of 356 patients were eligible for inclusion into the present study. The median (IQR) pretreatment serum BChE level was 6180 (4990-7710) IU/l. Lower serum BChE levels were associated with lower BMI (p < 0.001), advanced tumor stage (p = 0.04), poor treatment response (p = 0.002), the occurrence of disease recurrence (p = 0.003), and the risk of death (p < 0.001). In uni- and multivariate analyses, low pretreatment serum BChE levels were independently associated with shorter PFS (HR 1.8 [1.2-2.6]; p = 0.002), CSS (HR 2.2 [1.4-3.5], p < 0.001), and OS (HR 2.0 [1.4-2.9]; p < 0.001). CONCLUSIONS: Low pretreatment serum BChE levels are associated with advanced tumor stage and poor response to treatment, and serve as an independent prognostic biomarker for shorter PFS, CSS, and OS in patients with cervical cancer treated with primary (chemo-)radiation therapy.

Low Plasma Cholinesterase Activity is Associated With Postoperative Delirium After Noncardiac Surgery in Elderly Patients: AProspective Observational Study.

BACKGROUND: Postoperative delirium (POD) commonly occurs in elderly patients after noncardiac surgery, resulting in increased morbidity and greater risk of death. However, its pathophysiology is currently unknown. Cholinergic dysfunction has been implicated in delirium pathophysiology, and low plasma cholinesterase activity has been reported as a risk marker of POD. OBJECTIVE: Therefore, the aim of this study was to investigate the link between plasma cholinesterase activity and POD in elderly Han Chinese patients after noncardiac surgery. METHOD: From January 2014 to January 2016, a cohort of 206 patients aged ≥ 60years who underwent noncardiac surgery and were transferred to the surgical intensive care unit were enrolled. POD was assessed using the Confusion Assessment Method for Intensive Care Unit. Clinical data including sex, age, general comorbidities, alcohol consumption, Acute Physiology and Chronic Health Evaluation (APACHE) II score, and type of surgery were recorded. Blood was drawn postoperatively to measure cholinesterase activity. Using multiple logistic regression analyses, the associations between cholinesterase activity and POD were examined, adjusting for potential confounding variables. RESULTS: Delirium incidence was 22.3%. POD was associated with cholinesterase activity, age, and APACHE II score. In multiple logistic regression analyses, lower acetylcholinesterase and butyrylcholinesterase activity were independent risk factors for POD. CONCLUSION: Plasma cholinesterase activity may be a candidate biomarker for POD after noncardiac surgery in the elderly Chinese Han population.

Occupational exposure to pesticides and thyroid function in Brazilian soybean farmers.

INTRODUCTION: Agriculture production has been supported especially by the use of pesticides for crop protection and pest control. Although the agricultural production has been increased by pesticides use, these substances also reach non-target organisms and may become a risk to the health of farmers. Several epidemiological studies in human have investigated the association between exposure to pesticides and altered serum levels of thyroid hormones, reporting both positive and negative results. Overall, the impact of pesticides on human thyroid function is still limited. OBJECTIVE: The aim of this study was to access serum levels of free thyroxin (FT4), total triiodothyronine (TT3), thyroid-stimulating hormone (TSH), and butyrylcholinesterase (BChE) in soybean farmers in southern Brazil. METHODS: The exposed group was composed by 46 rural workers and 27 subjects not exposed to pesticides composed the control group. All subjects had blood samples collected by venipuncture in order to analyze the serum levels of FT4, TT3, TSH and BChE. RESULTS: The results showed a significant decreasing in TSH and increasing in TT3 and FT4 in rural workers, compared to control group. BChE levels were lower in exposed group than in control group. The results suggest that farmers are exposed to mixtures of pesticides with endocrine disruptor properties.

Relevance of peripheral cholinesterase activity on postoperative delirium in adult surgical patients (CESARO): A prospective observational cohort study.

BACKGROUND: The cholinergic system is considered to play a key role in the development of postoperative delirium (POD), which is a common complication after surgery. OBJECTIVES: To determine whether peri-operative acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities are associated with the development of POD in in-hospital surgical patients, and raise hypotheses on cholinergic regulatory mechanisms in POD. DESIGN: A prospective multicentre observational study by the Peripheral Cholinesterase-activity on Neurocognitive Dysfunctions in Surgical Patients (CESARO) study group. SETTING: Nine German hospitals. PATIENTS: Patients of at least 18 years of age scheduled for inpatient elective surgery for a variety of surgical procedures. A total of 650 patients (mean age 61.5 years, 52.8% male) were included. METHODS: Clinical variables, and peripheral AChE and BuChE activities, were assessed throughout the peri-operative period using bedside point-of-care measurements (one pre-operative and two postoperative measurements). POD screening was conducted postoperatively for at least 24 h and up to the third postoperative day using a validated screening tool (nursing delirium screening scale). RESULTS: In all, 179 patients (27.5%) developed POD within the early postoperative phase. There was a lower BuChE activity in patients with delirium compared with patients without delirium pre-operatively (Cohen's r = 0.07, P = 0.091), on postoperative day 1 (Cohen's r = 0.12, P = 0.003) and on postoperative day 2 (Cohen's r = 0.12, P = 0.002). In contrast, there was a significantly higher AChE activity in patients with delirium compared with patients without delirium pre-operatively (Cohen's r = 0.10, P = 0.012), on postoperative day 1 (Cohen's r = 0.11, P = 0.004) and on postoperative day 2 (Cohen's r = 0.13, P = 0.002). After adjusting for covariates in multiple logistic regression, a significant association between both BuChE and AChE activities and POD was not found. However, in the multivariable analysis using the Generalized Estimating Equation, cholinesterase activities showed that a decrease of BuChE activity by 100 U L increased the risk of a delirium by approximately 2.1% (95% CI 1.6 to 2.8%) and for each 1 U g of haemoglobin increase in AChE activity, there was a 1.4% (95% CI 0.6 to 2.2%) increased risk of POD. CONCLUSION: Peri-operative peripheral cholinesterase activities may be related to the development of POD, but the clinical implications remain unclear. Further studies, in homogeneous patient groups with a strict protocol for measurement time points, are needed to investigate the relationship between cholinesterase activities and POD. TRIAL REGISTRATION: www.clinicaltrials.gov. Identifier NCT01964274.

Effect of pesticide exposure on the cholinesterase activity of the occupationally exposed tea garden workers of northern part of West Bengal, India.

Context: Pesticide poisoning and related deaths are a global concern, but there is little information about its effect on the occupationally exposed tea garden workers of North Bengal. Objective: This study investigates the level of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in the blood of the tea garden workers at risk of exposure to a mixture of pesticides. Materials and methods: The study sample consisted of pesticide exposed workers, non-exposed (control), smokers and alcoholics. AChE and BuChE activity was measured and tested for significance. Results: Results showed that AChE activity was half in the pesticide exposed individuals than controls (p≤ 0.001). BuChE activity was also significantly decreased in the pesticide exposed individuals than controls (p≤ 0.001), while AChE and BuChE activity in smokers and alcoholics were not different from that of controls. However, significantly decreased AChE and BuChE activities were recorded in pesticide exposed workers compared to smokers and alcoholics. Conclusions: The results indicated that the decrease in enzyme activities in tea garden workers was due to mixed pesticides (containing organophosphates) exposure. Age was not found to influence the enzyme activities. However, the gender had little effect on the enzyme activities but the effect was not so prominent.

Biomonitoring of blood cholinesterases and acylpeptide hydrolase activities in rural inhabitants exposed to pesticides in the Coquimbo Region of Chile.

In Chile, agriculture is a relevant economic activity and is concomitant with the use of pesticides to improve the yields. Acute intoxications of agricultural workers occur with some frequency and they must be reported to the surveillance system of the Ministry of Health. However the impacts of chronic and environmental pesticide exposure have been less studied. Among pesticides frequently used in Chile for insects control are organophosphates (OP) and carbamates (CB). They are inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). In this study we determined the pattern of both biomarkers activity in three populations with different type of chronic exposure to OP/CB: environmentally exposed (EE), occupationally exposed (OE) and a reference group (RG) without exposure. Besides this, we also measured the activity of acylpeptide hydrolase (APEH), an enzyme involved in relevant functions in the central synapses that is also expressed in erythrocytes and previously reported to be highly inhibited by some OP. A baseline measurement was done in both exposure groups and then a second measurement was done during the spraying season. The RG was measured only once at any time of the year. Our results indicate that people under chronic OP/CB exposure showed an adaptive response through an increase of basal BChE activity. During the spray season only BChE activity was decreased in the EE and OE groups (p<0.05 and p<0.01, respectively) and the higher magnitude of BChE inhibition was observed in the EE group. The analysis of the frequencies of inhibition above 30% (biological tolerance limit declared by Chilean legislation) indicated that BChE was most frequently inhibited in the EE group (53% of the individuals displayed inhibition) and AChE in the OE group (55% of the individuals displayed AChE inhibition). APEH activity showed the highest frequency of inhibition in the EE group independent of its magnitude (64%). Our results demonstrate that the rural population living nearby agricultural settings displays high levels of environmental exposure. APEH activity seems to be a sensitive biomarker for acute low-level exposure and its usefulness as a routine biomarker must to be explored in future studies. Systematic biomonitoring and health outcomes studies are necessary as well as obtaining the baseline for BChE and AChE activity levels with the aim to improve environmental and occupational health policies in Chile.

Simultaneous detection of dual biomarkers from humans exposed to organophosphorus pesticides by combination of immunochromatographic test strip and ellman assay.

A novel sandwich immunoassay based immunochromatographic test strip (ICTS) has been developed for simultaneously measuring both butyrylcholinesterase (BChE) activity and the total amount of BChE (including inhibited and active enzyme) from 70 µLpost-exposure human plasma sample. The principle of this method is based on the BChE monoclonal antibody (MAb) capable of acting as both capture antibody and detection antibody. The BChE MAb which was immobilized on the test line was able to recognize both organophosphorus BChE adducts (OP-BChE) and BChE and provided equal binding affinity, permitting detection of the total enzyme amount in post-exposure human plasma samples. The formed immunocomplexes on the test line can further be excised from the test-strip for subsequent off-line measurement of BChE activity using the Ellman assay. Therefore, dual biomarkers of BChE activity and phosphorylation (OP-BChE) will be obtained simultaneously. The whole sandwich-immunoassay was performed on one ICTS, greatly reducing analytical time. The ICTS sensor showed excellent linear responses for assaying total amount of BChE and active BChE ranging from 0.22 to 3.58nM and 0.22-7.17nM, respectively. Both the signal detection limits are 0.10nM. We validated the practical application of the proposed method to measure 124 human plasma samples from orchard workers and cotton farmers with long-term exposure to organophosphorus pesticides (OPs). The results were in highly agreement with LC/MS/MS which verified our method is extremely accurate. Combining the portability and rapidity of test strip and the compatibility of BChE MAb as both capture antibody and detection antibody, the developed method provides a baseline-free, low-cost and rapid tool for in-field monitoring of OP exposures.

Redox-Controlled Fluorescent Nanoswitch Based on Reversible Disulfide and Its Application in Butyrylcholinesterase Activity Assay.

Butyrylcholinesterase (BChE) mainly contributing to plasma cholinesterase activity is an important indicator for routinely diagnosing liver function and organophosphorus poisoning in clinical diagnosis, but its current assays are scarce and frequently suffer from some significant interference and instability. Herein, we report a redox-controlled fluorescence nanoswtich based on reversible disulfide bonds, and further develop a fluorometric assay of BChE via thiol-triggered disaggregation-induced emission. Thiol-functionalized carbon quantum dots (thiol-CQDs) with intense fluorescence is found to be responsive to hydrogen peroxide, and their redox reaction transforms thiol-CQDs to nonfluorescent thiol-CQD assembly. The thiols inverse this process by a thiol-exchange reaction to turn on the fluorescence. The fluorescence can be reversibly switched by the formation and breaking of disulfide bonds caused by external redox stimuli. The specific thiol-triggered disaggregation-induced emission enables us to assay BChE activity in a fluorescence turn-on and real-time way using butyrylthiocholine iodide as the substrate. As-established BChE assay achieves sufficient sensitivity for practical determination in human serum, and is capable of avoiding the interference from micromolar glutathione and discriminatively quantifying BChE from its sister enzyme acetylcholinesterase. The first design of reversible redox-controlled nanosiwtch based on disulfide expands the application of disulfide chemistry in sensing and clinical diagnostics, and this novel BChE assay enriches the detection methods for cholinesterase activity.

Alterations in acetylcholinesterase and butyrylcholinesterase activities in chronic obstructive pulmonary disease: relationships with oxidative and inflammatory markers.

This work focused on finding a relationship between acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities and the development and severity of COPD. The possible link of these enzymes to oxidative and inflammatory processes was also investigated. The study included 229 healthy controls and 153 COPD patients. Erythrocyte AChE and plasma BChE activities were determined using spectrophotometric methods. Markers related to the oxidative status including thiobarbituric acid-reactive substances (TBARS), total protein carbonyls (PCs), advanced oxidation protein products (AOPP), reduced glutathione, nitric oxide, and peroxynitrite were measured. We also evaluated the activity of glutathione peroxidase, catalase, and superoxide dismutase in the plasma and erythrocytes. Serum levels of IL-6 and TNF-α were measured by the enzyme-linked immunosorbent assay. COPD patients showed increased AChE and BChE activities in comparison to healthy controls. Interestingly, AChE activity was higher in COPD smokers than in nonsmokers, while no difference was revealed for BChE. In addition, our results showed an inverse correlation between AChE activity and the levels of IL-6 in COPD smokers. Positive correlations were found, in COPD smokers, between plasma BChE activity and the levels of several biomarkers of protein oxidative damage including AOPP and PC. Our findings suggest that the alterations in AChE and BChE activities may be related to the oxidative and inflammatory processes in COPD patients rendering these enzymes as markers of COPD disease.