Serum pseudocholinesterase and very-low-density lipoprotein metabolism

Reactivators of butyrylcholinesterase inhibited by organophosphorus compounds

In this review, the current progress in the research and development of butyrylcholinesterase (BChE) reactivators is summarised and the advantages or disadvantages of these reactivators are critically discussed. Organophosphorus compounds such as nerve agents (sarin, tabun, VX) or pesticides (chlorpyrifos, diazinon) cause irreversible inhibition of acetylcholinesterase (AChE) and BChE in the human body. While AChE inhibition can be life threatening due to cholinergic overstimulation and crisis, selective BChE inhibition has presumably no adverse effects. Because BChE is mostly found in plasma, its activity is important for the scavenging of organophosphates before they can reach AChE in the central nervous system. Therefore, this enzyme in combination with its reactivator can be used as a pseudo-catalytic scavenger of organophosphates. Three structural types of BChE reactivators were found, i.e. bisquaternary salts, monoquaternary salts and uncharged compounds. Although the reviewed reactivators have certain limitations, the promising candidates for BChE reactivation were found in each structural group.

Butyrylcholinesterase and lipid metabolism: Possible dual role in metabolic disorders

Butyrylcholinesterase (BChE), an enzyme primarily found in the liver, plasma, and brain, has been recognized for its role in the hydrolysis of choline esters. Recent studies have shed light on its involvement in lipid metabolism, revealing its potential as a crucial player in maintaining lipid homeostasis. However, the interactions between external factors and BChE activity in lipid metabolic pathways remain a complex subject of study. This review summarizes the current knowledge regarding BChE activity and lipid metabolism and seeks to clarify the nature of this relationship as causal or consequential. Evidence supports the role of BChE in energy homeostasis disruption, such as obesity and related metabolic disorders, where it exhibits lipolytic activity and mediates fatty acid use and storage. The unexpected functions of BChE in lipoprotein synthesis and the impact of polymorphic variants of the BCHE gene suggest a central role in lipid metabolism; however, further investigation is needed to confirm and describe these functions, especially considering the metabolic context. Furthermore, exploring therapeutic interventions in lipid metabolism disorders contributes to elucidating their implications on BChE activity, but attention to the metabolic status and genotypes as possible factors in this interaction is needed. In summary, further research in this field holds promise for improving our understanding of the complex interplay between BChE and lipid metabolism, and its potential clinical applications. However, the available data corroborate the dual role of BChE activity, both as a critical responsive element to metabolic challenges and as a predisposition factor to metabolic diseases.

Possible Role of Butyrylcholinesterase in Fat Loss and Decreases in Inflammatory Levels in Patients with Multiple Sclerosis after Treatment with Epigallocatechin Gallate and Coconut Oil: A Pilot Study

(1) Background. Multiple sclerosis (MS) is characterised by the loss of muscle throughout the course of the disease, which in many cases is accompanied by obesity and related to inflammation. Nonetheless, consuming epigallocatechin gallate (EGCG) and ketone bodies (especially β-hydroxybutyrate (βHB)) produced after metabolising coconut oil, have exhibited anti-inflammatory effects and a decrease in body fat. In addition, butyrylcholinesterase (BuChE), seems to be related to the pathogenesis of the disease associated with inflammation, and serum concentrations have been related to lipid metabolism. Objective. The aim of the study was to determine the role of BuChE in the changes caused after treatment with EGCG and ketone bodies on the levels of body fat and inflammation state in MS patients. (2) Methods. A pilot study was conducted for 4 months with 51 MS patients who were randomly divided into an intervention group and a control group. The intervention group received 800 mg of EGCG and 60 mL of coconut oil, and the control group was prescribed a placebo. Fat percentage and concentrations of the butyrylcholinesterase enzyme (BuChE), paraoxonase 1 (PON1) activity, triglycerides, interleukin 6 (IL-6), albumin and βHB in serum were measured. (3) Results. The intervention group exhibited significant decreases in IL-6 and fat percentage and significant increases in BuChE, βHB, PON1, albumin and functional capacity (determined by the Expanded Disability Status Scale (EDSS)). On the other hand, the control group only exhibited a decrease in IL-6. After the intervention, BuChE was positively correlated with the activity of PON1, fat percentage and triglycerides in the intervention group, whereas these correlations were not observed in the control group (4). Conclusions. BuChE seems to have an important role in lipolytic activity and the inflammation state in MS patients, evidenced after administering EGCG and coconut oil as a βHB source.

Multivalent butyrylcholinesterase inhibitor discovered by exploiting dynamic combinatorial chemistry

In this study, we report the generation of a polymer-based dynamic combinatorial library (DCL) incorporating exchangeable side chains using acylhydrazone formation reaction. In combination with tetrameric butyrylcholinesterase (BChE), the most potent binding side chain was identified, and the information obtained was further used for the synthesis of a multivalent BChE inhibitor. In the in vitro biological evaluation, this multivalent inhibitor exhibited not only better inhibitory effect than the commercial reference but also high selectivity on BChE over acetylcholinesterase (AChE).

Relationship between butyrylcholinesterase activity and lipid parameters in workers occupationally exposed to pesticides

Exposure to organophosphate pesticides (OP) has been associated with the inhibition of cholinesterase enzymatic activity, such as butyrylcholinesterase (BuChE). Changes in BuChE activity have been associated with obesity, diabetes, hyperthyroidism, and metabolic syndrome. However, few studies have evaluated the effects of pesticides on both BuChE and lipid parameters. The aim of this study was to evaluate lipid parameters in urban sprayers and their association with BuChE activity. An analytical cross-sectional study was conducted in workers exposed to pesticides. The pesticide exposures were evaluated by the measurement of urinary dialkylphosphates. BuChE activity was determined spectrophotometrically in serum, and biochemical parameters were determined at a certified laboratory. Information regarding general characteristics, lifestyle, and other aspects was obtained from a structured questionnaire. The results showed variations in glucose, cholesterol, albumin, atherogenic index, creatinine, LDL, VLDL, triglycerides, and total lipids according to the level of exposure to pesticides in individuals with overweight and obesity. Furthermore, positive correlations between BuChE activity and lipid parameters were observed; these effects were associated with the body mass index. More studies are needed in human population to better elucidate the role of BuChE in lipid metabolism.

Diagnoses of Pathological States Based on Acetylcholinesterase and Butyrylcholinesterase

Two cholinesterases exist: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). While AChE plays a crucial role in neurotransmissions, BChE has no specific function apart from the detoxification of some drugs and secondary metabolites from plants. Thus, both AChE and BChE can serve as biochemical markers of various pathologies. Poisoning by nerve agents like sarin, soman, tabun, VX, novichok and overdosing by drugs used in some neurodegenerative disorders like Alzheimer´s disease and myasthenia gravis, as well as poisoning by organophosphorus pesticides are relevant to this issue. But it appears that changes in these enzymes take place in other processes including oxidative stress, inflammation, some types of cancer and genetically conditioned diseases. In this review, the cholinesterases are introduced, the mechanism of inhibitors action is explained and the relations between the cholinesterases and pathologies are explained.

Cholinergic control of bone development and beyond

There is ample evidence that cholinergic actions affect the health status of bones in vertebrates including man. Nicotine smoking, but also exposure to pesticides or medical drugs point to the significance of cholinergic effects on bone status, as reviewed here in Introduction. Then, we outline processes of endochondral ossification, and review respective cholinergic actions. In Results, we briefly summarize our in vivo and in vitro studies on bone development of chick and mouse [1,2], including (i) expressions of cholinergic components (AChE, BChE, ChAT) in chick embryo, (ii) characterisation of defects during skeletogenesis in prenatal ChE knockout mice, (iii) loss-of-function experiments with beads soaked in cholinergic components and implanted into chicken limb buds, and finally (iv) we use an in vitro mesenchymal 3D-micromass model that mimics cartilage and bone formation, which also had revealed complex crosstalks between cholinergic, radiation and inflammatory mechanisms [3]. In Discussion, we evaluate non-cholinergic actions of cholinesterases during bone formation by considering: (i) how cholinesterases could function in adhesive mechanisms; (ii) whether and how cholinesterases can form bone-regulatory complexes with alkaline phosphatase (ALP) and/or ECM components, which could regulate cell division, migration and adhesion. We conclude that cholinergic actions in bone development are driven mainly by classic cholinergic, but non-neural cycles (e.g., by acetylcholine); in addition, both cholinesterases can exert distinct ACh-independent roles. Considering their tremendous medical impact, these results bring forward novel research directions that deserve to be pursued.

The diagnostic and prognostic value of paraoxonase-1 and butyrylcholinesterase activities compared with acute-phase proteins in septic dogs and stratified by the acute patient physiologic and laboratory evaluation score

BACKGROUND

Sepsis is a complex syndrome that involves an increased oxidative stress status and dysregulation of cholinergic neurotransmission. Paraoxonase-1 (PON-1) and butyrylcholinesterase (BChE) activities have been identified as significant biomarkers to monitor such disorders in human septic patients.

OBJECTIVE

We aimed to determine the diagnostic and prognostic value of PON-1 and BChE vs other traditional acute-phase proteins such as albumin (ALB) and C-reactive protein (CRP) in septic dogs.

METHODS

This prospective observational study included 20 dogs with a diagnosis of sepsis, 27 with low-grade systemic inflammation (LGSI), and 10 healthy dogs that served as controls. Plasma samples were obtained from all dogs for analysis on admission, and then every 24-48 hours until discharge or death in the septic group.

RESULTS

Dogs with sepsis had lower PON-1 activity compared with dogs in the LGSI group (1.1 ± 0.10 vs 1.6 ± 0.08 U/mL, P = .002), but no differences in BChE activity were detected between the groups. PON-1, ALB, and CRP could successfully discriminate healthy animals from those with sepsis looking at the area under the curve (AUC) of the receiver operator characteristics curves (ROCs), which were 0.828, 0.903 and 1.000, respectively. Finally, although no differences were found among the groups for PON-1 or BChE activity, the nonsurvivor septic dogs had higher CRP (P = .002), lower ALB (P = .025) levels, and tended to have lower PON-1 (P = .082) activities than the survivors at patient death or discharge.

CONCLUSION

Septic dogs showed lower plasma PON-1 and higher BChE activities, but only PON-1 activity correlated with disease severity. Further studies are warranted to describe the usefulness of these new biomarkers of sepsis progression and recovery in dogs.

Plasma cholinesterase is associated with Chinese adolescent overweight or obesity and metabolic syndrome prediction

Purpose: To determine the plasma concentrations of butyrylcholinesterase (BChE), also known as pseudocholinesterase, in different weight categories of adolescents, and to explore the possible association between plasma BChE and overweight (OW), obesity, and metabolic syndrome (MetS) in Chinese adolescents. Patients and methods: This cross-sectional study included 1,236 Chinese adolescents (194 obese [OB], 188 OW, 732 normal weight [NW], and 122 underweight [UW]). The biochemical variables and anthropometric variables of the study participants were evaluated. Plasma BChE level was measured by DGKC method. Results: OB was associated with a higher prevalence of upper strata plasma BChE levels when compared with the BChE levels in UW, NW, and OW group. A logistic regression analysis showed that plasma BChE was positively associated with the OB group when compared with the NW group. Boys in the OW group, but not the OB group, had a significantly higher prevalence of upper stratum of BChE levels. Plasma triglyceride, total cholesterol, low-density lipoprotein-cholesterol, and ApoB levels were positively associated with the upper stratum of BChE levels when compared with lower stratum. MetS and most of its components were more prevalent among subjects with upper stratum rather than lower stratum BChE levels. Receiver operating characteristic curves for plasma BChE in subjects with MetS indicated that the AUC was 0.80 (95%CI:0.70-0.90,P<0.001) and 0.89 (95%CI:0.82-0.95,P<0.001) in girls and boys, respectively. After adjusting for age, the multivariate-adjusted odds ratio for MetS in the upper stratum of BChE levels was 8.73 (95%CI: 3.49-21.84) in the boys cohorts and also in the girls cohorts (OR=1.71, 95%CI: 1.35-21.70). Conclusion: This study confirmed an association between BChE levels and weight status in Chinese adolescents, and demonstrated that the upper strata of plasma BChE levels were associated with being OW, and even more highly associated with obesity. Plasma BChE levels were positively associated with MetS and its components and could be useful for identifying adolescents with MetS.

Acetylcholinesterase and Butyrylcholinesterase – Important Enzymes of Human Body

The serine hydrolases and proteases are a ubiquitous group of enzymes that is fundamental to many critical lifefunctions. Human tissues have two distinct cholinesterase activities: acetylcholinesterase and butyrylcholinesterase. Acetylcholinesterase functions in the transmission of nerve impulses, whereas the physiological function of butyrylcholinesterase remains unknown. Acetylcholinesterase is one of the crucial enzymes in the central and peripheral nerve system. Organophosphates and carbamates are potent inhibitors of serine hydrolases and well suited probes for investigating the chemical reaction mechanism of the inhibition. Understanding the enzyme’s chemistry is essential in preventing and/or treating organophosphate and carbamate poisoning as well as designing new medicaments for cholinergic-related diseases like as Alzheimer’s disease.

Changes in Cholinesterase Activity in Blood of Adolescent with Metabolic Syndrome after Supplementation with Extract from Aronia melanocarpa

Obesity and metabolic syndrome (MetS) are growing problems among children and adolescents. There are no reports of changes in the activity of butyrylcholinesterase (BChE) in children and adolescents with metabolic syndrome especially after supplementation with extract from Aronia melanocarpa. Materials studied included plasma and erythrocytes isolated from peripheral blood of patients with MetS and healthy subjects. We have estimated the following parameters: acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity, lipid peroxidation and lipids levels in plasma, and erythrocytes membrane. In patients with MetS, a significant increase in AChE and BChE activity, higher LDL-cholesterol and triacylglycerol levels, and lower HDL-cholesterol level were observed. Supplementation with A. melanocarpa extract resulted in mild but statistically significant reduction of total cholesterol, LDL-cholesterol, and triacylglycerol levels and caused an increase in HDL-cholesterol level and a decrease in lipid peroxidation in plasma patients with MetS. Additionally, a decrease in lipid peroxidation and cholesterol level and a decrease in AChE activity in the erythrocyte membranes after supplementation with A. melanocarpa were noted. Summarizing, an increase in AChE and BChE activity and disruption of lipid metabolism in patients with MetS were observed. After supplementation of MetS patients with A. melanocarpa extract, a decrease in AChE activity and oxidative stress was noted.

Butyrylcholinesterase Levels on Admission Predict Severity and 12-Month Mortality in Hospitalized AIDS Patients

Background

Butyrylcholinesterase (BChE) is synthesized mainly in the liver and an important marker in many infectious/inflammatory diseases, but its role in acquired immunodeficiency syndrome (AIDS) patients is not clear. We wished to ascertain if BChE level is associated with the progression/prognosis of AIDS patients.

Methods

BChE levels (in U/L) were measured in 505 patients; <4500 was defined as “low” and ≥4500 as “normal.” Associations between BChE level and CD4 count, WHO stage, body mass index (BMI), C-reactive protein (CRP) level, and duration of hospitalization were assessed. Kaplan–Meier curves and Cox proportional hazards model were used to assess associations between low BChE levels and mortality, after adjustment for age, CD4 count, WHO stage, and laboratory parameters.

Results

A total of 129 patients (25.5%) had a lower BChE level. BChE was closely associated with CD4 count, WHO stage, CRP level, and BMI (all P < 0.001). Eighty-four patients (16.6%) died in the first year of follow-up. One-year survival was 64.5 ± 4.5% for patients with low BChE and 87.6 ± 1.8% for those with normal BChE (log-rank, P < 0.001). After adjustment for sex, age, BMI, WHO stage, and CD4 count, as well as serum levels of hemoglobin, sodium, and albumin, the hazard ratio was 1.8 (95% confidence interval, 1.0–3.2) for patients with a low BChE compared with those with a normal BChE (P = 0.035).

Conclusion

BChE level is associated with HIV/AIDS severity and is an independent risk factor for increased mortality in AIDS patients.

Decreased activity of butyrylcholinesterase in blood plasma of patients with chronic obstructive pulmonary disease

INTRODUCTION

Butyrylcholinesterase (BChE) is involved in the metabolism of endogenous lipids and xenobiotics, such as esters of carboxylic or phosphoric acids. Butyrylcholinesterase activity is associated with both inflammation and oxidative stress. Changes in the activity of this enzyme have been observed in various diseases such as liver cirrhosis, diabetes, neurodegenerative disease and others.

MATERIAL AND METHODS

The study involved 30 patients with chronic obstructive pulmonary disease (COPD) and 18 healthy subjects. The COPD patients were divided according to the severity of the disease by applying the classification of COPD based on GOLD standards for forced expiratory volume in 1 s (FEV₁) and the FEV₁/forced expiratory volume (FVC) ratio. The control group comprised blood samples collected from healthy subjects without concomitant diseases related to the respiratory system. Butyrylcholinesterase activity, lipid peroxidation and total antioxidant capacity (TAC) were determined in the blood plasma.

RESULTS

A significant (p < 0.05) decrease in the activity of BChE, associated with an increase in lipid peroxidation and a decrease in the total antioxidant capacity, was observed in blood plasma of patients with chronic obstructive pulmonary disease.

CONCLUSIONS

The study shows for the first time that activity of BChE in the blood plasma of patients diagnosed with chronic obstructive pulmonary disease is considerably reduced compared with healthy subjects. These changes were accompanied by a decrease of TAC and an increase of lipid peroxidation, which suggests that they may be related to the oxidative stress induced by COPD disease.

Recent progress in the identification of selective butyrylcholinesterase inhibitors for Alzheimer's disease

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative disorders with notable factor of dysfunction in cholinergic system. Low ACh level can be observed in the pathogenesis of AD. Several AChE inhibitors have already been used for clinical treatments. However, other than normal conditions, ACh is mostly hydrolyzed by BuChE in progressed AD. Account for an increased level of BuChE and decreased level of AChE in the late stage of AD, development of selective BuChE inhibitor is of vital importance. Up till now, compounds with various scaffolds have been discovered to selectively inhibit BuChE. Different effective anti-BuChE molecules are concluded in this review.

From Heart Failure to Highly Unsaturated Fatty Acid Deficiency and Vice Versa: Bidirectional Heart and Liver Interactions

BACKGROUND

In several trials, beneficial prognostic effects of highly unsaturated fatty acids (HUFAs) in heart failure were shown. Because other studies showed no incremental benefit in nearly preserved cardiac function, the question arises, whether the degree of cardiac dysfunction is involved. It is hypothesized that increased left ventricular (LV) wall stress affects the endogenous hepatic HUFA metabolism, which in turn exhibits adverse cardiac consequences.

METHODS

Cardiac magnetic resonance imaging was performed in 30 patients with suspected cardiomyopathy. The serum fatty acid profile was assessed using gas chromatography/mass spectrometry.

RESULTS

Docosahexaenoic acid (DHA; P = 0.002) and eicosapentaenoic acid (EPA; by trend) levels were decreased in patients with reduced LV ejection fraction (≤ 50%) or LV dilatation (≥ 90 mL/m(2)). Decreased DHA (P = 0.003) and EPA (P = 0.022) levels were associated with a reduced LV ejection fraction. Decreased DHA level was correlated with increased end-diastolic (P = 0.047) and end-systolic LV wall stress (P = 0.001). Pseudocholinesterase activity was inversely correlated with end-diastolic (P = 0.020) and end-systolic LV wall stress (P = 0.025).

CONCLUSIONS

DHA level was significantly reduced in heart failure. Similar, but less pronounced effects were found for EPA and arachidonic acid by trend. Increased LV wall stress was correlated with a reduced DHA level. Increased LV wall stress exhibits various adverse consequences (eg, increased oxygen consumption, favouring of arrhythmias, and an unfavourable remodelling). The increase of wall stress was paralleled by reduced HUFA level. Increased LV wall stress was correlated with reduced pseudocholinesterase, which is suggestive of hepatic congestion (ie, a cardiohepatic syndrome, involved in the altered fatty acid profile in heart failure) and has major consequences regarding the dose-efficacy of HUFA treatment.

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.

The Correlative Study of Serum Pseudo-cholinesterase, Biological Parameters and Symptoms Among Occupational Workers

Cholinesterase is one of many important enzymes needed for acetylcholine hydrolysis. This study aimed to evaluate the serum pseudo-cholinesterase (BuChE) level and its relation to biological parameters (hematological and biochemical parameters) and symptoms among occupational workers, gasoline station worker in Bangkok, Thailand. Our results revealed that the average BuChE level was in normal range, but it had strong relation to hemoglobin (Hb), hematocrit (Hct), blood urea nitrogen (BUN), creatinine (Cr) and serum glutamic pyruvic trans-aminase (SGPT) (Linear regression analysis, p < 0.05, p < 0.05, p < 0.01, p = 0.001 and p < 0.01 respectively). Although, BuChE was not related to white blood cell parameters, but it may exhibit the skin irritation (p = 0.058) of the workers as it showed significant correlation to conjunctivitis and nausea (Pearson's correlation, p < 0.01 and p < 0.05). In conclusion, this finding may explain that BuChE was significantly related to red blood cells (RBC), liver and kidney functions.

Possible Induction of Cholinesterase in Epileptic Patients Treated With Anticonvulsant Drugs: Relationship With Lipoprotein Levels

The effect of enzyme-inducing anticonvulsant drugs on the serum concentrations of lipoproteins has been widely studied. However, there is little agreement between the results with regard to the possible development of a lipoprotein profile related to an increased or decreased cardiovascular risk. It has been suggested that cholinesterase (ChE) could be induced by these drugs, something of undeniable interest as ChE appears to have a relation to the metabolism of lipoproteins. The serum activity of ChE was determined in a group of 90 adult epileptic patients (56 male and 34 female) treated with phenobarbital, phenytoin, and carbamazepine. The liver enzyme induction produced by these drugs was then evaluated by determining serum gamma-glutamyltranspherase activity and urinary excretion of D-glucaric acid. A significant increase of serum ChE (p < 0.005) was found in the group of patients compared to a control group (n = 49) with a similar distribution for age and sex. A significant correlation was found for both male and female patients between ChE and concentrations of triglycerides, phospholipids, cholesterol, low-density lipoprotein (LDL) phospholipids, LDL-cholesterol, and apolipoprotein B (p < 0.01). Similarly, in female patients, ChE had a significant correlation with the total cholesterol/high-density lipoprotein (HDL) cholesterol and LDL-cholesterol/HDL-cholesterol ratios (p < 0.01). The ChE/HDL-cholesterol relationship, which has been proposed as a marker for cardiovascular risk, presented significant correlations with the total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios in patients of both sexes (p < 0.001). In the case of epileptic patients treated with enzyme-inducing anticonvulsant drugs, there may be an association between the possible induction of ChE and the metabolism of lipoproteins containing apolipoprotein B.

Butyrylcholinesterase as a prognostic marker: a review of the literature

BACKGROUND

Butyrylcholinesterase (BChE) is an α-glycoprotein synthesized in the liver. Its serum level decreases in many clinical conditions such as acute and chronic liver damage, inflammation, injury and infections, and malnutrition.

METHODS AND RESULTS

This review collects the main evidence on the emerging role of butyrylcholinesterase as a prognostic marker of liver and nonliver diseases as well as a marker of protein-energy malnutrition and obesity. In fact, serum concentrations and BChE activity seem to accurately reflect the availability of amino acidic substrates and/or derangement in protein synthesis due to hepatocellular damage. In cancer, with or without liver impairment, serum BChE levels serve as an accurate functional and prognostic indicator, useful for monitoring clinical and therapeutic interventions according to patients' prognosis. In the absence of inflammation, BChE could also serve as an index of the effectiveness of nutritional support.

CONCLUSIONS

Serum BChE assessment should be included in routine clinical diagnostic procedures to evaluate patient clinical conditions, in particular in cases of inflammation and/or protein-energy malnutrition.

Liver hypertrophy: a review of adaptive (adverse and non-adverse) changes--conclusions from the 3rd International ESTP Expert Workshop

Preclinical toxicity studies have demonstrated that exposure of laboratory animals to liver enzyme inducers during preclinical safety assessment results in a signature of toxicological changes characterized by an increase in liver weight, hepatocellular hypertrophy, cell proliferation, and, frequently in long-term (life-time) studies, hepatocarcinogenesis. Recent advances over the last decade have revealed that for many xenobiotics, these changes may be induced through a common mechanism of action involving activation of the nuclear hormone receptors CAR, PXR, or PPARα. The generation of genetically engineered mice that express altered versions of these nuclear hormone receptors, together with other avenues of investigation, have now demonstrated that sensitivity to many of these effects is rodent-specific. These data are consistent with the available epidemiological and empirical human evidence and lend support to the scientific opinion that these changes have little relevance to man. The ESTP therefore convened an international panel of experts to debate the evidence in order to more clearly define for toxicologic pathologists what is considered adverse in the context of hepatocellular hypertrophy. The results of this workshop concluded that hepatomegaly as a consequence of hepatocellular hypertrophy without histologic or clinical pathology alterations indicative of liver toxicity was considered an adaptive and a non-adverse reaction. This conclusion should normally be reached by an integrative weight of evidence approach.

Impact of heavy metal pollution on the hemogram and serum biochemistry of the Libyan jird, Meriones libycus

The stress profiles of the hemogram and serum biochemistry were determined in the context of heavy metal (Cd, Cu, Hg, Ni and Pb) exposure in the wild libyan jird, Meriones libycus, from one of Riyadh's polluted areas versus a reference site. Coupling the pronounced drop in platelets (PLT) (28%) and mean platelet volume (MPV) (17%) with the insignificant responses of other red blood cell indices, suggests bone marrow suppression that is characterized by thrombocytopenia as an initial abnormality. The species-specific stress leukogram for M. libycus is expressed by leukocytosis (66%), monocytosis (40%), lymphocytosis (23%) with eosinopenia (81%) and neutropenia (42%). Hyperglycemia (50%), hyper-low-density-lipoproteinemia (38%), hypocortisolism (85%) and hypotriglyceridemia (55%) depicted serum biochemistry profile. In polluted jirds, the elevated activities of pseudocholinesterase (PChE) and serum marker enzymes (alanine aminotransferase ALT, aspartate aminotransferase AST and creatine kinase CK) strongly suggest functional damage of the liver and/or heart. A potential role of PChE in low-density lipoprotein (LDL) metabolism is implied in the joint rise of both indices and in the recognized relationship between PChE and lipid metabolites. While increased utilization in lipid metabolism and energy synthesis could rationalize the inhibition of the normal patterns of triglycerides and lactate dehydrogenase (LDH), the inhibited activities of LDH could additionally be attributed to its hormetic behavior towards low and high metal concentrations. The overall findings presented here documented the relevance of M. libycus in biomonitoring and predicting the risk imposed on human populations living in polluted areas.

GWAS of butyrylcholinesterase activity identifies four novel loci, independent effects within BCHE and secondary associations with metabolic risk factors

Serum butyrylcholinesterase (BCHE) activity is associated with obesity, blood pressure and biomarkers of cardiovascular and diabetes risk. We have conducted a genome-wide association scan to discover genetic variants affecting BCHE activity, and to clarify whether the associations between BCHE activity and cardiometabolic risk factors are caused by variation in BCHE or whether BCHE variation is secondary to the metabolic abnormalities. We measured serum BCHE in adolescents and adults from three cohorts of Australian twin and family studies. The genotypes from ∼2.4 million single-nucleotide polymorphisms (SNPs) were available in 8791 participants with BCHE measurements. We detected significant associations with BCHE activity at three independent groups of SNPs at the BCHE locus (P = 5.8 × 10(-262), 7.8 × 10(-47), 2.9 × 10(-12)) and at four other loci: RNPEP (P = 9.4 × 10(-16)), RAPH1-ABI2 (P = 4.1 × 10(-18)), UGT1A1 (P = 4.0 × 10(-8)) and an intergenic region on chromosome 8 (P = 1.4 × 10(-8)). These loci affecting BCHE activity were not associated with metabolic risk factors. On the other hand, SNPs in genes previously associated with metabolic risk had effects on BCHE activity more often than can be explained by chance. In particular, SNPs within FTO and GCKR were associated with BCHE activity, but their effects were partly mediated by body mass index and triglycerides, respectively. We conclude that variation in BCHE activity is due to multiple variants across the spectrum from uncommon/large effect to common/small effect, and partly results from (rather than causes) metabolic abnormalities.

Butyrylcholinesterase activity in young men and women: association with cardiovascular risk factors

OBJECTIVE

We investigated the relationship between butyrylcholinesterase (BuChE) and cardiovascular risk factors in young male and female.

DESIGN AND METHODS

The study comprised 1512 healthy subjects, 18-25 years of age. In fasting sera the concentrations of BuChE and cardiovascular risk factors were estimated.

RESULTS

Analysis of variance indicated significant increase in body mass index (BMI), total cholesterol (TC), triglycerides (TG), low-density lipoproteins (LDL) (p<0.05) and albumin (p<0.001) with BuChE activity increment in males. In females glucose and albumin (p<0.05) increased with BuChE activity. Negative but not significant correlation between BuChE and high-density lipoprotein cholesterol (HDL-C) was detected for both genders.

CONCLUSION

The tendency towards overweight in young male could explain our results on BMI as an independent risk factor for higher BuChE in young male. Glucose as an independent risk factor for higher BuChE activity in females indicates that BuChE may be a predictor of diabetes.

A practical guide for the stabilization of acylghrelin in human blood collections

OBJECTIVE AND METHODS

To better understand acylghrelin plasma stability, human synthetic acylghrelin was spiked into plasma and tracked by liquid chromatography tandem mass spectrometry. To investigate the best method for quantifying clinical plasma acylghrelin levels, pre- and postprandial human blood was collected from healthy volunteers (n=6) using various sample collections and treatments. Plasma ghrelin levels from human blood collections were analysed by enzyme-linked immunosorbant assay (ELISA).

RESULTS

Acylghrelin's half-life in plasma was approximately 45 min with the formation of des-acylghrelin approaching 50% before the end of the 60-min incubation. Loss of acylghrelin inversely correlated with an increase in des-acylghrelin (P<0.008; r(2) =0.870). Plasma pretreated with 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF) or protease inhibitor cocktail without acidification resulted in no detectible acylghrelin losses. Acylghrelin measurements with AEBSF-treated blood were minimally 40% higher than sodium citrate/citric acid, K(2) EDTA, aprotinin/HCl and P800 collections. HCl addition to AEBSF-treated plasma did not provide enhanced acylghrelin stability and induced deacylation at and above the 100 mM final concentration. Pre- and postprandial ghrelin attenuation was investigated using aprotinin/HCl, AEBSF, protease inhibitor cocktail and no treatment for blood and plasma preparations. Fasting samples treated with AEBSF and protease inhibitor cocktail were approximately threefold higher than aprotinin/HCl and control treatments (P<0.03). Pre- and postprandial ghrelin attenuation was approximately twofold different (P<0.04) with significant counterintuitive trends in aprotinin/HCl and K(2) EDTA groups.

CONCLUSIONS

Our data suggest that AEBSF addition to K(2) EDTA blood immediately after collection without plasma acidification, processing on ice and 14-day 70 °C storage is the best treatment for accurately quantifying acylghrelin in human plasma.

Butyrylcholinesterase in metabolic syndrome

Butyrylcholinesterase may have a role in a number of metabolic functions and could affect the expression of insulin resistance syndrome. We present our integrated work using clinical, biochemical and bioinformatic approaches to delineate the possible function of this enzyme. Initially, we constructed a phylogenic tree with nucleotides and amino acid sequences and showed the existence of similar sequences in bacteria, plants and in other animals. We also demonstrated a possible pathogenic role for BChE in the common existence of insulin resistance, type 2 diabetes and Alzheimer's disease by in silico method and followed it up with a diabetic mouse study where cognition was slowed along with changes in BChE levels. In the next group of in silico studies, we employed THEMATICS method to identify the amino acids at the active site and later performed docking studies with drugs. THEMATICS predicted two clusters of ionisable amino acid residues that are in proximity: one with two residues and another with 11 showed perturbation in the THEMATICS curves. Using ISIS/Draw 2.5SP4, ARGUSLAB 4.0.1 and HEX 5.1. software. 3-D ligands were docked with BChE motif (from PDB). We did not find any of the ligands studied with significant docking distance, indicating they did not have direct interaction with the active site. Subsequently we performed in silico studies to compare the secondary structure and domain of BChE. Protein-protein interaction showed the following intersections with BChE UBE21, CHAT, APOE, AATF, DF ALDH9A1, PDHX, PONI PSME3 and ATP6VOA2. The integrative physiological roles of proteins with poorly known functions can be approached by generating leads in silico, which can be studied in vivo, setting into movement an iterative process.

The butyrylcholinesterase knockout mouse a research tool in the study of drug sensitivity, bio-distribution, obesity and Alzheimer's disease

Butyrylcholinesterase (BChE) mutations common in the human population may result in complete or partial BChE deficiency, making the BChE knockout (KO) mouse a model for human deficiencies. The BChE KO mouse cannot tolerate standard doses of the muscle relaxant succinylcholine or the Alzheimer's disease drugs huperzine A and donepezil. It is resistant to the asthma drug bambuterol. The importance of BChE in detoxication of cocaine has been demonstrated by hepatotoxicity and cardiotoxicity in cocaine-challenged BChE KO mice. The BChE KO mouse becomes obese on a high-fat diet, suggesting a role for BChE in fat metabolism. BChE serves as a backup for acetylcholinesterase by hydrolyzing the neurotransmitter acetylcholine in acetylcholinesterase knockout mice. Imaging studies show that BChE injected intrathecally crosses the blood-brain barrier. Mice, but not humans, have carboxylesterase in their blood. Carboxylesterase obscures the role of BChE in detoxication of organophosphorus pesticides. Future studies will make a double knockout that has neither BChE nor carboxylesterase. The double knockout is expected to be unusually sensitive to the toxicity of organophosphorus pesticides. Knowledge of drug sensitivities in the mouse model of human BChE deficiency will aid in understanding adverse drug effects in humans.

Kinetic analysis of effector modulation of butyrylcholinesterase-catalysed hydrolysis of acetanilides and homologous esters

The effects of tyramine, serotonin and benzalkonium on the esterase and aryl acylamidase activities of wild-type human butyrylcholinesterase and its peripheral anionic site mutant, D70G, were investigated. The kinetic study was carried out under steady-state conditions with neutral and positively charged aryl acylamides [o-nitrophenylacetanilide, o-nitrotrifluorophenylacetanilide and m-(acetamido) N,N,N-trimethylanilinium] and homologous esters (o-nitrophenyl acetate and acetylthiocholine). Tyramine was an activator of hydrolysis for neutral substrates and an inhibitor of hydrolysis for positively charged substrates. The affinity of D70G for tyramine was lower than that of the wild-type enzyme. Tyramine activation of hydrolysis for neutral substrates by D70G was linear. Tyramine was found to be a pure competitive inhibitor of hydrolysis for positively charged substrates with both wild-type butyrylcholinesterase and D70G. Serotonin inhibited both esterase and aryl acylamidase activities for both positively charged and neutral substrates. Inhibition of wild-type butyrylcholinesterase was hyperbolic (i.e. partial) with neutral substrates and linear with positively charged substrates. Inhibition of D70G was linear with all substrates. A comparison of the effects of tyramine and serotonin on D70G versus the wild-type enzyme indicated that: (a) the peripheral anionic site is involved in the nonlinear activation and inhibition of the wild-type enzyme; and (b) in the presence of charged substrates, the ligand does not bind to the peripheral anionic site, so that ligand effects are linear, reflecting their sole interaction with the active site binding locus. Benzalkonium acted as an activator at low concentrations with neutral substrates. High concentrations of benzalkonium caused parabolic inhibition of the activity with neutral substrates for both wild-type butyrylcholinesterase and D70G, suggesting multiple binding sites. Benzalkonium caused linear, noncompetitive inhibition of the positively charged aryl acetanilide m-(acetamido) N,N,N-trimethylanilinium for D70G, and an unusual mixed-type inhibition/activation (alpha > beta > 1) for wild-type butyrylcholinesterase with this substrate. No fundamental difference was observed between the effects of ligands on the butyrylcholinesterase-catalysed hydrolysis of esters and amides. Thus, butyrylcholinesterase uses the same machinery, i.e. the catalytic triad S198/H448/E325, for the hydrolysis of both types of substrate. The differences in response to ligand binding depend on whether the substrates are neutral or positively charged, i.e. the differences depend on the function of the peripheral site in wild-type butyrylcholinesterase, or the absence of its function in the D70G mutant. The complex inhibition/activation effects of effectors, depending on the integrity of the peripheral anionic site, reflect the allosteric 'cross-talk' between the peripheral anionic site and the catalytic centre.

Mechanisms and outcomes of drug- and toxicant-induced liver toxicity in diabetes

Increase dincidences of hepatotoxicity have been observed in diabetic patients receiving drug therapies. Neither the mechanisms nor the predisposing factors underlying hepatotoxicity in diabetics are clearly understood. Animal studies designed to examine the mechanisms of diabetes-modulated hepatotoxicity have traditionally focused only on bioactivation/detoxification of drugs and toxicants. It is becoming clear that once injury is initiated, additional events determine the final outcome of liver injury. Foremost among them are two leading mechanisms: first, biochemical mechanisms that lead to progression or regression of injury; and second, whether or not timely and adequate liver tissue repair occurs to mitigate injury and restore liver function. The liver has a remarkable ability to repair and restore its structure and function after physical or chemical-induced damage. The dynamic interaction between biotransformation-based liver injury and compensatory tissue repair plays a pivotal role in determining the ultimate outcome of hepatotoxicity initiated by drugs or toxicants. In this review, mechanisms underlying altered hepatotoxicity in diabetes with emphasis on both altered bioactivation and liver tissue repair are discussed. Animal models of both marked sensitivity (diabetic rats) and equally marked protection (diabetic mice) from drug-induced hepatotoxicity are described. These examples represent a remarkable species difference. Availability of the rodent diabetic models offers a unique opportunity to uncover mechanisms of clinical interest in averting human diabetic sensitivity to drug-induced hepatotoxicities. While the rat diabetic models appear to be suitable, the diabetic mouse models might not be suitable in preclinical testing for potential hepatotoxic effects of drugs or toxicants, because regardless of type 1 or type2 diabetes, mice are resistant to acute drug-or toxicant-induced toxicities.

Alzheimer's disease and type 2 diabetes mellitus: the cholinesterase connection?

Alzheimer's disease and type 2 diabetes mellitus tend to occur together. We sought to identify protein(s) common to both conditions that could suggest a possible unifying pathogenic role. Using human neuronal butyrylcholinesterase (AAH08396.1) as the reference protein we used BLAST Tool for protein to protein comparison in humans. We found three groups of sequences among a series of 12, with an E-value between 0–12, common to both Alzheimer's disease and diabetes: butyrylcholinesterase precursor K allele (NP_000046.1), acetylcholinesterase isoform E4-E6 precursor (NP_000656.1), and apoptosis-related acetylcholinesterase (1B41|A). Butyrylcholinesterase and acetylcholinesterase related proteins were found common to both Alzheimer's disease and diabetes; they may play an etiological role via influencing insulin resistance and lipid metabolism.

Relationship between serum butyrylcholinesterase and the metabolic syndrome

OBJECTIVE

To identify independent predictors of serum butyrylcholinesterase (BuChE) activity and examine its relationship with the metabolic syndrome.

DESIGN AND METHODS

Serum BuChE activity was measured and metabolic syndrome risk factors were assessed in 1097 healthy subjects recruited from the Newfoundland adult population.

RESULTS

Serum BuChE activity was related to insulin homeostasis and correlated with fasting insulin levels (r = 0.266, P < 0.001) and insulin resistance (HOMA-R) index (r = 0.292, P < 0.001) and was higher in individuals with risk factors for the metabolic syndrome. BuChE activity was higher in males than in females and correlated most strongly with serum triglyceride levels (r = 0.363, P < 0.001) and indicators of abdominal obesity (r = 0.355, P < 0.001). Percent trunk fat (beta = 0.185, P < 0.001), triglyceride levels (beta = 0.225, P < 0.001), sex (beta = -0.202, P = 0.001), glucose (beta = 0.209, P < 0.001), insulin (beta = 0.360, P = 0.011), HOMA-R (beta = -0.319, P = 0.044), and age (beta = 0.086, P = 0.002) were independent predictors of BuChE activity.

CONCLUSIONS

These results suggest the involvement of BuChE in the pathophysiological process constituting the metabolic syndrome. Whether increased BuChE activity precedes or follows the development of risk factors is not known.

Serum cholinesterase activity in diabetes and associated pathologies

Serum cholinesterase activity was measured in diabetes, hypertensive and diabetic/hypertensive patients. The sample consisted of volunteer patients and was divided in a control group (n=26), type 2 diabetic group (n=16), hypertensive group (n=12) and type 2 diabetic/hypertensive group (n=26). In addition, blood glucose, cholesterol and triglyceride levels were determined. Serum cholinesterase activity in the control group was significantly lower in relation to the other groups (p<0.001). Blood glucose levels were elevated in type 2 diabetic and type 2 diabetic/hypertensive groups. In vitro studies showed increased cholinesterase activity in the presence of glucose 5-100mM or insulin 0.5-25 UI (p<0.001). Cholesterol and triglycerides were at normal levels only in the control group. Possibly, a relationship exists between the increase in serum cholinesterase and the vascular complications in the diabetic patients, potentially stimulated by the levels of glycemia and dyslipidemia. Although patients were receiving different medicines, the increase in enzyme activity was similar in all groups. This enzymatic profile suggests a possible interference of the diseases in the catalytic mechanism of the serum cholinesterase enzyme.

Butyrylcholinesterase: association with the metabolic syndrome and identification of 2 gene loci affecting activity

BACKGROUND

Plasma cholinesterase activity is known to be correlated with plasma triglycerides, HDL- and LDL-cholesterol, and other features of the metabolic syndrome. A role in triglyceride metabolism has been proposed. Genetic variants that decrease activity have been studied extensively, but the factors contributing to overall variation in the population are poorly understood. We studied plasma cholinesterase activity in a sample of 2200 adult twins to assess covariation with cardiovascular risk factors and components of the metabolic syndrome, to determine the degree of genetic effects on enzyme activity, and to search for quantitative trait loci affecting activity.

METHODS AND RESULTS

Cholinesterase activity was lower in women than in men before the age of 50, but increased to activity values similar to those in males after that age. There were highly significant correlations with variables associated with the metabolic syndrome: plasma triglyceride, HDL- and LDL-cholesterol, apolipoprotein B and E, urate, and insulin concentrations; gamma-glutamyltransferase and aspartate and alanine aminotransferase activities; body mass index; and blood pressure. The heritability of plasma cholinesterase activity was 65%. Linkage analysis with data from the dizygotic twin pairs showed suggestive linkage on chromosome 3 at the location of the cholinesterase (BCHE) gene and also on chromosome 5.

CONCLUSIONS

Our results confirm and extend the connection between cholinesterase, cardiovascular risk factors, and metabolic syndrome. They establish a substantial heritability for plasma cholinesterase activity that might be attributable to variation near the structural gene and at an independent locus.

Effects of switching pravastatin to cerivastatin on C-reactive protein, butyrylcholinesterase, and lipids

OBJECTIVE

C-reactive protein (CRP) concentrations, butyrylcholinesterase (BChE) activity, total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TG) were evaluated in patients switched from pravastatin to cerivastatin. The purpose of this study was to determine whether a more potent statin (cerivastatin) would further affect CRP, whether a relation ship between CRP and BChE existed, and if there were any relationships between CRP or BChE and lipids. In view of the withdrawal of cerivastatin from the market, studies considering the effects of conversion of patients from one statin to another are warranted.

RESEARCH DESIGN AND METHODS

Thirty-seven patients actively taking pravastatin (10 mg-40 mg) were switched to cerivastatin (0.2 mg-0.8 mg) at the initial visit in the Lipid Clinic at David Grant Medical Center, Travis Air Force Base. Samples were collected before the conversion (pravastatin phase) and at 6 weeks and 12 weeks post-conversion. Patients were excluded from the study if they were taking gemfibrozil concomitantly. Patients were counseled on the adverse effects of cerivastatin, including rhabdomyolsis.

RESULTS

Median CRP levels at the pravastatin phase, 6 weeks of cerivastatin, and 12 weeks of cerivastatin, were 0.380 mg/dL, 0.403 mg/dL, and 0.364 mg/dL (p = 0.772), respectively. Median BChE activity at the pravastatin phase, 6 weeks of cerivastatin, and 12 weeks of cerivastatin were 0.338 micromol/mL/min, 0.332 micromol/mL/min, 0.33 micromol/mL/min (p = 0.746), respectively. A negative correlation was observed between CRP and BChE at baseline only (r = -0.353, p = 0.032). There was a significant decline in mean TC (p < 0.001) and median LDL (p < 0.001) and a significant increase in mean HDL (p = 0.017) over the three time points. Numerically TG declined, but it was not statistically significant (p = 0.649). No correlations were observed between CRP or BChE and any of the lipids. Gender, aspirin use, and the presence of CHD or diabetes did not affect CRP levels or BChE activity.

CONCLUSION

Median CRP remained stable with pravastatin and cerivastatin use, although TC and LDL decreased. The further decline observed with LDL, but not CRP suggests differing effects of statins on LDL and CRP. Limitations include no serum levels prior to statin use and small sample size; thus, future studies are needed to address the relationship between cholesterol and CRP and the mechanism of action of statins on CRP.

Increased serum butyrylcholinesterase activity in type IIb hyperlipidaemic patients

The inheritance of the apolipoprotein E4 (APOE4) allele has been shown to increase the plasma cholesterol level, but little information is as concerns the association of the APOE genotype and hyperlipidaemia and the activities of two serum enzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Blood samples from 55 type IIb hyperlipidaemic, non-demented patients and 55 age- and sex-matched controls were therefore examined in this pilot study. A significantly increased BChE activity was found in the serum of type IIb hyperlipidaemic patients, but the AChE activity did not differ significantly as compared with that in the control group. The APOE4 allele was significantly overrepresented among the hyperlipidaemic probands, but neither serum cholinesterase activity was affected by the dosage of the APOE4 gene. Our results point to a possible association between an abnormal lipid metabolism and the BChE activity and might have implications as regards the pathomechanism of both Alzheimer's and vascular dementias and the cholinesterase inhibitor therapy of dementing disorders.

Selective activity of butyrylcholinesterase in serum by a chemiluminescent assay

In a previous study, we showed that purified commercial esterase activity can be detected in a chemiluminescent assay based on the hydrolysis of 2-methyl-1-propenylbenzoate (MPB) to 2-methyl-1-propenol, which is subsequently oxidized by the horseradish peroxidase (HRP)-H(2)O(2) system. The purpose of this study was to verify the applicability of this assay to human serum. The existence of an esterase activity capable of hydrolysing MPB is indicated by the fact that the MPB-serum-HRP-H(2)O(2) system consumes oxygen and emits light. Both signals were abolished by prior serum heat inactivation and were preserved when serum was stored at < or =4 degrees C. Addition of aliesterase inhibitors, such as fluoride ion and trichlorfon or the cholinesterase inhibitor eserine, totally prevents light emission. The butyrylcholinesterase-specific substrate benzoylcholine causes a delay in both O(2) uptake and light emission, while the specific acetylcholinesterase substrate, acetyl-beta-methylcholine, had practically no effect. Purified butyrylcholinesterase, but not acetylcholinesterase, triggered light emission. The finding that butyrylcholinesterase is responsible for the hydrolysis of MPB in serum should serve as the basis for the development of a specific chemiluminescent assay for this enzyme.

Acetyl- and butyrylcholinesterase in normal and diabetic rat retina

We studied the composition of molecular forms of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in normal and streptozotocin-induced diabetic rat retinas. Tissues were sequentially extracted with saline (S1) and saline-detergent buffers (S2). 50% decrease in the amphiphilic G4 and G1 AChE molecular forms was observed in the diabetic retina compared to the controls. Less than 5% of the cholinesterase activity was due to BChE. 60% of the BChE activity in normal retina was brought into solution and evenly distributed between S1 and S2. In spite of the low BChE activity in the retina it was possible to detect globular forms (G(A)1, G(A)2, G(A)4, G(H)4) and a small proportion of an asymmetric form (A12) in the S1 extract. The G(A)4 and G(A)1 forms were found in the S2 extract. In the diabetic retina the activity of G(A)4 and G(A)1 BChE molecular forms was reduced 60% and 40% respectively. Our results indicate that diabetes caused a remarkable decrease in the activity of cholinesterase molecular forms in the retina. These decrease might participate in the alterations observed in the diabetic retina.

From pseudocholinesterase to human immunodeficiency virus

Pseudocholinesterase is a protein for which no function exists in mammals including human beings. To date, no substrate has been identified for this 'enzyme'. Involvement of this protein in the aetiopathogenesis of many diseases, such as hyperlipoproteinaemia, is still actively debated. Here, we propose a theoretical method to immobilize pseudocholinesterase in hepatocytes using antibody bound to liposomes. Conceptually, this approach will have widespread application, especially in blocking human immunodeficiency virus replication in vivo.