Changes In Acetylcholinesterase Activity Research Articles

Evaluation of Changes in Acetylcholinesterase Activity in Workers of Mehriz Elixir Pesticide Plant in Yazd

Background and Aims: Some pesticide chemical compounds, such as organophosphates and carbamates, interfere with or inhibit cholinesterase activity. Employees working in pesticide factories are one of the groups at risk of pesticide poisoning. This study aimed to evaluate the effect of work on exposure to toxins on the serum level of erythrocyte cholinesterase activity.
 Materials and Methods: This research was conducted on Mehriz Elixir Pesticide Factory workers. Blood samples were taken from 76 employees in 2 groups as a control group, and 38 workers were exposed to organophosphorus toxins three months after starting work in a factory. Cholinesterase activity was analyzed using the Elman method, and data were analyzed using SPSS software version 22.
 Results: The mean age of the subjects was 35.07 years, which was 35.26 in the exposure group (n = 38) and 34.89 in the control group (n = 38). The activity of acetylcholinesterase enzyme in the control group at 0, 10, and 20 minutes was 12.78 ku/l, 14.24 ku/l, and 15.45 ku/l, respectively. The acetylcholinesterase enzyme activity in the exposed group was 10.77 ku/l, 10.40 ku/l, and 10.36 ku/l at 0, 10, and 20 minutes, respectively. At all stages, the mean acetylcholinesterase activity in the control group was higher than the exposed group, but significant differences were observed at 10 and 20 minutes between the 2 groups.
 Conclusion: Exposure of workers to organophosphate inhibits acetylcholinesterase, which manifests by a decrease in the activity of this enzyme.

CHALCONE ANALOGUES AS POTENTIAL MEDICINES OF PATHOGENETIC THERAPY OF ALZHEIMER'S DISEASE: IN VITRO SCREENING

Introduction. Alzheimer's disease is one of the most common forms of dementia, the pathogenesis of which is based on the accumulation of β–amyloid plaques in brain structures and the development of cholinergic deficiency. The aim of the study was to evaluate the effect of chalcone analogues on the change in acetylcholinesterase activity and the process of β-amyloid aggregation in vitro. Material and methods. The tested compounds were six bis-substituted chalcone analogues, which were dissolved in dimethylsulfoxide during the analysis to obtain double dilutions. The effect of the studied substances on the activity of acetylcholinesterase was evaluated by the modified Ellman method. The change in the aggregation process of β-amyloid particles was determined in reaction with congo red after 3, 6 and 9 days of incubation. Based on the obtained results of the «% inhibition- concentration» relationships, the IC50 index was calculated, which was expressed in mmol/ml. Results. In the course of the study, it was shown that the analyzed chalcone analogues inhibit the aggregation of β-amyloid particles starting from the 6th day of incubation with a maximum on the 9th day. At the same time, the compounds that showed the highest level of activity were trimethoxy-substituted substances under the codes AZBAX4 and AZBAX6, whose IC50 on the 9th day of the study was 21.4±0.928 mmol/ml and 32.4±0.456 mmol/ml, respectively. Also, a high level of anticholinesterase properties was established for these compounds with IC50 of 35.9±0.991mmol/ml and 25.1±0.261 mmol/ml, respectively. The rest of the tested compounds showed a lower level of activity. Conclusion. The study showed that chalcone analogues under the codes AZBAX4 and AZBAX6 inhibit the activity of acetylcholinesterase and the pro-cess of aggregation of β-amyloid in vitro, which makes these compounds promising for further study in order to develop medicines for the pathogenet-ic treatment of Alzheimer's disease.

Cytogenotoxic potential and toxicity in adult Danio rerio (zebrafish) exposed to chloramine T

Background Chloramine-T (CL-T) is a synthetic sodium salt used as a disinfectant in fish farms to combat bacterial infections in fish gills and skin. While its efficacy in pathogen control is well-established, its reactivity with various functional groups has raised concerns. However, limited research exists on the toxicity of disinfection by-products to aquatic organisms. Therefore, this study aims to assess the sublethal effects of CL-T on adult zebrafish by examining biomarkers of nucleus cytotoxicity and genotoxicity, acetylcholinesterase (AChE) inhibition, and histopathological changes. Methods Male and female adult zebrafish (wildtype AB lineage) specimens were exposed to 70, 140, and 200 mg/L of CL-T and evaluated after 96 h. Cytotoxic and genotoxic effects were evaluated by estimating the frequencies of nuclear abnormalities (NA), micronuclei (MN), and integrated optical density (IOD) of nuclear erythrocytes. Histopathological changes in the gills and liver were assessed using the degree of tissue changes (DTC). AChE activity was measured in brain samples. Results and conclusions At a concentration of 200 mg/L, NA increased, indicating the cytogenotoxic potential of CL-T in adult zebrafish. Morphological alterations in the nuclei were observed at both 70 and 200 mg/L concentrations. Distinct IOD profiles were identified across the three concentrations. There were no changes in AChE activity in adult zebrafish. The DTC scores were high in all concentrations, and histological alterations suggested low to moderate toxicity of CL-T for adult zebrafish.

Integrated in vivo and in silico evaluation of sweet basil oil as a protective agent against cisplatin-induced neurotoxicity in mice

BackgroundCisplatin is a wide-ranging antineoplastic drug. Neurotoxicity is one of cisplatin’s side effects that restrict its usage. This study aimed to investigate the possible protective properties of sweet basil oil against cisplatin-induced neurotoxicity in mice. A docking study was carried out to elucidate the fundamental mechanism of sweet basil oil’s ameliorative influence. Thirty male mice were allocated into three groups as follows: control group, cisplatin group (2.3 mg/kg), and sweet basil oil group (25 µl/kg basil oil + cisplatin 2.3 mg/kg). Cisplatin was given for five successive days, followed by five days of rest, for two cycles, while sweet basil oil was orally administered for 21 successive days.ResultsOur results revealed that sweet basil oil’s antioxidant activity ameliorated the oxidative stress induced by cisplatin in mice’s brains via lowering MDA levels and increasing CAT activity and Nrf2 levels. Also, the anti-apoptotic activity of sweet basil oil was obvious via lowering the gene expression levels of Bid and caspase-3 but did not affect the serum level of P38 MAPK. Changes in acetylcholinesterase activity, serotonin and dopamine levels induced by cisplatin were significantly alleviated by sweet basil oil.ConclusionSweet basil oil can be used as a food supplement to guard against cisplatin-induced neurotoxicity.Graphical abstract

Structural and molecular cholinergic imaging markers of cognitive decline in Parkinson's disease.

Cognitive decline in Parkinson's disease is related to cholinergic system degeneration, which can be assessed in vivo using structural MRI markers of basal forebrain volume and PET measures of cortical cholinergic activity. In the present study we aimed to examine the interrelation between basal forebrain degeneration and PET-measured depletion of cortical acetylcholinesterase activity as well as their relative contribution to cognitive impairment in Parkinson's disease. This cross-sectional study included 143 Parkinson's disease participants without dementia and 52 healthy control participants who underwent structural MRI, PET scanning with 11C-methyl-4-piperidinyl propionate (PMP) as a measure of cortical acetylcholinesterase activity, and a detailed cognitive assessment. Based on the fifth percentile of the overall cortical PMP PET signal from the control group, people with Parkinson's disease were subdivided into a normo-cholinergic (n = 94) and a hypo-cholinergic group (n = 49). Volumes of functionally defined posterior and anterior basal forebrain subregions were extracted using an established automated MRI volumetry approach based on a stereotactic atlas of cholinergic basal forebrain nuclei. We used Bayesian t-tests to compare basal forebrain volumes between controls, and normo- and hypo-cholinergic Parkinson's participants after covarying out age, sex and years of education. Associations between the two cholinergic imaging measures were assessed across all people with Parkinson's disease using Bayesian correlations and their respective relations with performance in different cognitive domains were assessed with Bayesian ANCOVAs. As a specificity analysis, hippocampal volume was added to the analysis. We found evidence for a reduction of posterior basal forebrain volume in the hypo-cholinergic compared to both normo-cholinergic Parkinson's disease [Bayes factor against the null model (BF10) = 8.2] and control participants (BF10 = 6.0), while for the anterior basal forebrain the evidence was inconclusive (BF10 < 3). In continuous association analyses, posterior basal forebrain volume was significantly associated with cortical PMP PET signal in a temporo-posterior distribution. The combined models for the prediction of cognitive scores showed that both cholinergic markers (posterior basal forebrain volume and cortical PMP PET signal) were independently related to multi-domain cognitive deficits, and were more important predictors for all cognitive scores, including memory scores, than hippocampal volume. We conclude that degeneration of the posterior basal forebrain in Parkinson's disease is accompanied by functional cortical changes in acetylcholinesterase activity and that both PET and MRI cholinergic imaging markers are independently associated with multi-domain cognitive deficits in Parkinson's disease without dementia. Comparatively, hippocampal atrophy only seems to have minimal involvement in the development of early cognitive impairment in Parkinson's disease.

An alien metabolite vs. a synthetic chemical hazard: An ecotoxicological comparison in the Mediterranean blue mussel

Bioactive natural products from marine invasive species may dramatically impact native communities, while many synthetic pharmaceutical drugs are released into the marine environment and have long-lasting harmful effects on aquatic life. Sometimes, metabolites from alien species and synthetic compounds share similar mechanisms of action, suggesting comparable ecotoxicological impacts. This applies to the alkaloid caulerpin (CAU) from the green algae Caulerpa cylindracea, highly invasive in the Mediterranean Sea, and to the synthetic lipid-lowering drug fenofibrate (FFB), both acting as agonists of peroxisome proliferator-activated receptors (PPARs). Analogies with FFB, which is widely considered hazardous to the aquatic environment, have led to concerns about the ecotoxicological potential of CAU. The problem has implications for public health as CAU is well known to enter the food web accumulating in fish of commercial importance. Here, we compared the effects of FFB and CAU through biochemical and histopathological analysis on a relevant bioindicator molluscan species, the mussel Mytilus galloprovincialis. Under laboratory conditions, mussels were fed with food enriched with CAU or FFB. After treatment, biochemical markers were analyzed revealing metabolic capacity impairments, cellular damage, and changes in acetylcholinesterase activity in mussels fed with FFB-enriched food. NMR-based metabolomic studies also showed significant alterations in the metabolic profiles of FFB-treated mussels. In addition, dietary administration of FFB produced morphological alterations in the mussels' gills and digestive tubules. Obtained results confirm that FFB is harmful to aquatic life and that its release into the environment should be avoided. Conversely, dietary treatment with CAU did not produce any significant alterations in the mussels. Overall, our results pave the way for the possible valorization of the huge biomass from one of the world's worst invasive species to obtain CAU, a natural product of interest in drug discovery.

Cadmium effects on the freshwater teleost Prochilodus lineatus: Accumulation and biochemical, genotoxic, and behavioural biomarkers

In order to evaluate the effects of Cd, juveniles of the Neotropical fish Prochilodus lineatus were exposed to 1 and 10 μg L-1 Cd, for 24 and 96 h. Fish exposed to Cd showed metal accumulation in the gills, kidney, and liver, an increase in DNA damage in erythrocytes, and an increase in lipid peroxidation (LPO) in the kidney. Cd exposure also caused a reduction in catalase activity, metallothionein induction, and LPO in the liver. Cd stimulated the swimming activity of exposed fish, resulting in longer swimming times and distances travelled, especially for the shortest exposure time. Changes in acetylcholinesterase activity (AChE) in the muscle and brain are probably related to these behavioural responses. These results show that Cd affects the functioning of several organs in P. lineatus, which is indicated by the genotoxic damage and changes in the AChE and swimming pattern of the exposed fish.

In a secondary analysis from a randomised, double-blind placebo-controlled trial Dexmedetomidine blocks cholinergic dysregulation in delirium pathogenesis in patients with major surgery

Dexmedetomidine is an alpha-2 adrenoreceptor agonist with anti-inflammatory and anti-delirogenic properties. Pathogenesis of postoperative delirium (POD) includes cholinergic dysfunction and deregulated inflammatory response to surgical trauma. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are discussed as biomarkers for both POD and severity in acute inflammation. To show whether there is a link between blood cholinesterase activities and dexmedetomidine, we performed a secondary analysis of a randomised, double-blind, placebo-controlled trial that recently showed a lower incidence of POD in the dexmedetomidine group. Abdominal or cardiac surgical patients aged ≥ 60 years were randomised to receive dexmedetomidine or placebo intra- and postoperatively in addition to standard general anaesthesia. We analysed the course of perioperative cholinesterase activities of 56 patients, measured preoperatively and twice postoperatively. Dexmedetomidine resulted in no change in AChE activity and caused a rapid recovery of BChE activity after an initial decrease, while placebo showed a significant decrease in both cholinesterase activities. There were no significant between-group differences at any point in time. From these data it can be assumed that dexmedetomidine could alleviate POD via altering the cholinergic anti-inflammatory pathway (CAIP). We advocate for further investigations to show the direct connection between dexmedetomidine and cholinesterase activity.

Dynamics of Changes in Acetylcholinesterase Activity in the Brain and Bood of Rats During Pharmacological Correction of Seizures Caused by Carbamate

To simulate a convulsive syndrome, phenylcarbamate was administered intraperitoneally at a dose of 1 mg/kg. Valproic acid aminoester (43 mg/kg), caramiphene (50 mg/kg), and diferidine (2 mg/kg) were investigated as potential anticonvulsant drugs. Blood and brain tissue for the determination of acetylcholinesterase (AСhE) were taken at 10, 30, 60 minutes, 6 and 24 hours after administration of the xenobiotic. In case of poisoning with reversible inhibitors of AChE and accumulation of acetylcholine in the CNS synapses (due to inhibition of AChE activity), only the initial manifestations of convulsive activity are caused, and other mechanisms not associated with AChE inhibition are responsible for the processes of further maintenance and recurrence of seizures.

Can Lemna minor mitigate the effects of cadmium and nickel exposure in a Neotropical fish?

We aimed to evaluate if Lemna minor can mitigate the observed effects of cadmium (Cd) and nickel (Ni) exposure in Prochilodus lineatus. Fish were exposed for 96 h to 20 µg L-1 of Cd, 1.5 mg L-1 of Ni, or to a mixture of these two metals. In all tests, one group was exposed to the metals with duckweed on the water surface, and other group was exposed only to the metals, without plants. After each exposure, samples of P. lineatus tissues were collected to evaluate multiple biomarkers. Duckweed prevented bioaccumulation in some fish tissues and attenuated changes in acetylcholinesterase activity, increases in erythrocytic nuclear abnormality frequency, and hyperglycemia. However, the changes in plasma ion concentrations, reduction in activity of ion transport enzymes, and histological damage were not mitigated. Therefore, we concluded that L. minor partially attenuates the effects caused by Cd and Ni exposure.

Biomarker responses in zebrafish (Danio rerio) following long-term exposure to microplastic-associated chlorpyrifos and benzo(k)fluoranthene.

Continuously increasing plastic production causes a constant accumulation of microplastic particles (MPs) in the aquatic environment, especially in industrialized and urbanized areas with elevated wastewater discharges. This coincides with the release of persistent organic pollutants (polycyclic aromatic hydrocarbons (PAHs), pesticides) entering limnic ecosystems. Although the assessment of potential effects of environmental pollutants sorbed to MPs under chronic exposure scenarios seems vital, data on potential hazards and risk by combined exposure to pollutants and microplastics for aquatic vertebrates is still limited. Therefore, zebrafish (Danio rerio) were exposed over 21 days to the organophosphate insecticide chlorpyrifos (CPF; 10 and 100ng/L) and the PAH benzo(k)fluoranthene (BkF; 0.78 and 50µg/L) either dissolved directly in water or sorbed to different MPs (irregular polystyrene, spherical polymethyl methacrylate; ≤ 100µm), where CPF was sorbed to polystyrene MPs and BkF was sorbed to polymethyl methacrylate MPs. Contaminant sorption to MPs and leaching were documented using GC-EI-MS; potential accumulation was studied in cryosections of the gastrointestinal tract. Enzymatic biomarkers and biotransformation were measured in liver and brain. Overall, exposure to non-contaminated MPs did not induce any adverse effects. Results of fluorescence tracking, CYP1A modulation by BkF as well as changes in acetylcholinesterase activity (AChE) by CPF were less pronounced when contaminants were sorbed to MPs, indicating reduced bioavailability of pollutants. Overall, following exposure to waterborne BkF, only minor amounts of parent BkF and biotransformation products were detected in zebrafish liver. Even high loads of MPs and sorbed contaminants did not induce adverse effects in zebrafish; thus, the potential threat of MPs as vectors for contaminant transfer in limnic ecosystems can be considered limited.

Effects of Aluminium Contamination on the Nervous System of Freshwater Aquatic Vertebrates: A Review.

Aluminium (Al) is the most common natural metallic element in the Earth’s crust. It is released into the environment through natural processes and human activities and accumulates in aquatic environments. This review compiles scientific data on the neurotoxicity of aluminium contamination on the nervous system of aquatic organisms. More precisely, it helps identify biomarkers of aluminium exposure for aquatic environment biomonitoring in freshwater aquatic vertebrates. Al is neurotoxic and accumulates in the nervous system of aquatic vertebrates, which is why it could be responsible for oxidative stress. In addition, it activates and inhibits antioxidant enzymes and leads to changes in acetylcholinesterase activity, neurotransmitter levels, and in the expression of several neural genes and nerve cell components. It also causes histological changes in nerve tissue, modifications of organism behaviour, and cognitive deficit. However, impacts of aluminium exposure on the early stages of aquatic vertebrate development are poorly described. Lastly, this review also poses the question of how accurate aquatic vertebrates (fishes and amphibians) could be used as model organisms to complement biological data relating to the developmental aspect. This “challenge” is very relevant since freshwater pollution with heavy metals has increased in the last few decades.

Titanium Dioxide Nanoparticles Are Toxic for the Freshwater Mussel Unio ravoisieri: Evidence from a Multimarker Approach

The current work investigated the ecotoxicological effects induced by Titanium Dioxide (TiO2) nanoparticles (NPs), used at three different concentrations (C1 = 10 μg·L−1, C2 = 100 μg·L−1 and C3 = 1000 μg·L−1) in a laboratory experiment, on the freshwater mussel Unio ravoisieri. Biochemical analyses of gills and digestive glands revealed a stress-related disruption of the antioxidant system. The catalase activity and the rates of malonedialdehyde and hydrogen peroxide production were significantly higher in both organs following the exposure to TiO2 NPs and was concentration-dependent. In addition, based on the observed changes in acetylcholinesterase activity, it can be concluded that the disturbance threshold for the cholinergic system was less than 1 mg·L−1 of TiO2. Overall, the results suggest that the mussel Unio ravoisieri could be used as a sentinel species in monitoring surveys assessing the environmental impact of metallic nanoparticles in freshwater systems.

Impact of chronic sub-lethal methylparaben exposure on cardiac hypoxia and alterations in neuroendocrine factors in zebrafish model.

Endocrine-disrupting chemicals have been shown to cause toxicity in different systems of the body including the endocrine, cardiovascular and nervous systems. This study aims to analyze the adverse effects of Methylparaben (MP) on cardiac functions, neurodevelopment, and behavior of zebrafish. Adult male and female zebrafish were exposed to MP for 30 days to study the toxicity effects. Zebrafish were grouped into control, solvent control, 1/10th (110 ppb), 1/100th, and 1/1000th (1 ppb) lethal concentration 50 of MP. Neurobehavioral assays, acetylcholinesterase (AChE) activity, serotonin levels, and expression of genes-Hypoxia-inducible factor 1 alpha, Neurotrophic Receptor Tyrosine Kinase, Paired box protein Pax-6, and tnnt2 were investigated in zebrafish. Results of the study showed more anxiety-like behavior in MP-treated female zebrafish when compared to males on chronic exposure. There was a dose-dependent reduction of AChE activity in both male and female zebrafish. Female zebrafish showed a dose-dependent increase in serotonin level on MP exposure while male zebrafish showed a dose-independent decrease in serotonin level. On MP exposure, there was also a dose-dependent dysregulation in the expression of cardiac hypoxia and neuronal differentiation-related genes in female zebrafish while a dose-independent change was observed in male zebrafish. Chronic MP exposure affects cardiac functions, neuronal functions, and behavior of zebrafish by exhibiting changes in AChE activity, serotonin levels, and altering the expression of genes related to cardiac hypoxia and neuronal differentiation even at sub-lethal doses.

Neuroprotective effects of Huperzine-A in aluminum induced neurotoxicity in hippocampus of mice

Exposure to aluminum has been correlated with the epidemiology of Alzheimer’s disease. Huperzine A (HupA), derived from the Chinese herb Huperzia serrata, is an inhibitor of acetylcholinesterase (AChE). However, its use in aluminum induced neurotoxicity has not been reported. The objective of the study was to examine the effect of HupA on aluminum-induced changes in AChE activity and hippocampal neurotoxicity. Aged female swiss albino mice were divided into five groups (n=10). Aluminum treated group (Al-S) received 30 mg/Kg of aluminum chloride (AlCl3) intraperitoneally (IP) for two weeks followed by IP normal saline. Three HupA treated groups received similar IP dosage of AlCl3 for two weeks followed by HupA 0.1 mg/Kg, HupA 0.2 mg/Kg and HupA 0.5 mg/kg. Control group received IP normal saline. At the end of week 4, AChE was estimated, and pyramidal neurons of hippocampus were counted. Al-S group showed an increase in mean brain AChE and Al-HupA 0.1 reduced it significantly (p&lt;0.05). Reduction in mean neuronal density in Al-S group, was comparatively more in CA3 hippocampal area (p&lt;0.001). Quantitative study found that 0.2mg/Kg of synthetic Huperzine A given intraperitoneally, was able to increase neuronal count significantly compared to 0.1mg/Kg and 0.5mg/Kg of Huperzine A.

Cotreatment of Small Gold Nanoparticles Protects Against the Increase in Cerebral Acetylcholinesterase Activity and Oxidative Stress Induced by Acute Ethanol Exposure in the Zebrafish

Gold nanoparticles (GNP) have emerged as an alternative to biomaterials in biomedical applications. Research has clearly demonstrated the relative safety and low toxicity of these molecules. However, the possible neuroprotective effect of GNP on the central nervous system (CNS) and its relationship with neurological and psychiatric disorders remain unclear. Zebrafish is a reliable model to investigate the impact of ethanol (EtOH) consumption on the CNS, including reward signaling such as the cholinergic neurotransmission system. Here, we investigated whether cotreatment or pretreatment with GNP prevented EtOH-induced changes in acetylcholinesterase activity and oxidative stress in the brain of zebrafish. We exposed adult zebrafish to 2.5 mg·L−1 GNP 1 h prior to EtOH (1% v/v) treatment for 1 h, and cotreated adult zebrafish simultaneously with both substances for 1 h. Pretreatment with GNP did not prevent EtOH-induced increase in the acetylcholinesterase activity, whereas cotreatment with 2.5 mg·L−1 GNP and EtOH protected against this increase. The results also suggested similar protective effect on oxidative stress parameters in the zebrafish pretreated with GNP at 2.5 mg·L−1. GNP significantly decreased the levels of thiobarbituric acid reactive species and dihydrodichlorofluorescein levels when cotreated with EtOH. GNP also prevented EtOH-induced increase in superoxide dismutase and catalase activities, suggesting a modulatory role of GNP in enzymatic antioxidant defenses. Our results showed that GNP was able to modulate the disruption of cholinergic and oxidative homeostasis in the brain of zebrafish. These findings indicate for the first time that zebrafish is an interesting perspective to investigate nanoparticles against disorders related to alcohol abuse.

Carbon nanofibers are bioaccumulated in Aphylla williamsoni (Odonata) larvae and cause REDOX imbalance and changes of acetylcholinesterase activity

Carbon-based materials have been considered very promising for the technological industry due to their unique physical and chemical properties, namely: ability to reduce production costs and to improve the efficiency of several products. However, there is little information on what is the level of exposure that leads to adverse effects and what kind of effects is expected in aquatic biota. Thus, the aim of the present study was to evaluate the toxicity of carbon nanofibers (CNFs) in dragonfly larvae (Aphylla williamsoni) based on predictive oxidative-stress biomarkers, antioxidant activity reduction and neurotoxicity. After ephemeral models' exposure to CNFs (48 h; at 500 μg/L), data have shown that these pollutants did not change larvae's nutritional status given the concentration of total soluble carbohydrates, total proteins and triglycerides in them. However, the levels of both nitric oxide and substances reactive to thiobarbituric acid (lipid peroxidation indicators) have increased and the antioxidant activity based on total thiol levels and on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (%) has reduced, and it suggests REDOX imbalance induction by CNFs. In addition, larvae exposed to these pollutants showed significant acetylcholinesterase activity reduction in comparison to the control group. Thus, the present study has brought further knowledge about how carbon-based materials can affect benthic macroinvertebrates and emphasized their ecotoxicological potential in freshwater environments.

AChE-activity in critically ill patients with suspected septic encephalopathy: a prospective, single-centre study

BackgroundUp to 70% of septic patients develop a diffuse brain dysfunction named “septic associated encephalopathy” which is often solely based on clinical impressions. However, the diagnosis of septic associated encephalopathy is outcome-relevant due to an increase in mortality in these patients. Neuroinflammation as well as a disturbance of cholinergic transmission are assumed to be the causes of both delirium and septic associated encephalopathy. An alteration in cholinergic activity can be objectified by measuring the erythrocytic acetylcholinesterase-activity. Single-point measurements of acetylcholinesterase-activity are of limited value because individual and dynamic changes over time have to be anticipated. Therefore, the hypothesis should be tested whether a longitudinal analysis of acetylcholinesterase-activity in critically ill patients can help to diagnose a suspected septic-associated encephalopathy and whether acetylcholinesterase-activity differs in comparison to non-septic patients.MethodsIn this prospective, observational, single-center study, 175 patients (45 with sepsis, 130 without sepsis) were included. All patients were admitted to the surgical Intensive Care Unit of the University hospital Ulm, Germany. Patients were examined daily for the presence of delirium using the CAM-ICU. Daily measurement of the acetylcholinesterase-activity was performed in all patients. The possible time-dependent change in acetylcholinesterase-activity was analyzed with a linear regression model considering repeated measurements. Using a time-adjusted model further factors able to affect AChE-activity were investigated. For nonparametric distributions quantitative data were compared using Wilcoxon matched-pairs test. For analysis of independent samples the Mann-Whitney test was performed.ResultsAbout 90% of septic patients with suspected septic associated encephalopathy exhibited a statistically significant time-dependent in- or decrease in acetylcholinesterase-activity over a period of at least 5 consecutive days.ConclusionLongitudinal measurement of acetylcholinesterase-activity over several consecutive days revealed a change from baseline only in septic patients with suspected septic-associated encephalopathy. Therefore, longitudinal measurement of acetylcholinesterase-activity is able to diagnose septic associated encephalopathy in septic patients with delirious symptoms.Trial registrationRetrospectively registered at German Clinical Trials Register, registration number DRKS00020542, date of registration: January 27, 2020.

Caffeic acid and caffeine attenuate toxicity associated with malonic or methylmalonic acid exposure in Drosophila melanogaster.

The deficiency in the activity of the mitochondrial enzyme methylmalonyl-CoA mutase (MCM, EC 5.4.99.2) leads to a condition called methylmalonic academia, which is characterised by the accumulation of methylmalonic (MMA), malonic (MA) or other organic acids. Importantly, we have recently found that supplementation with Ilex paraguariensis aqueous extract offered protection against toxicity associated with MMA or MA exposure to Drosophila melanogaster. Of note, caffeic acid (CA) and caffeine (CAF) were the major phytochemicals found in our Ilex paraguariensis crude extract. Therefore, here, we have exploited CA and/or CAF to test the hypothesis that supplementation with the isolated compounds (either alone or combined) could exert a protective effect against MMA or MA-induced toxicity in flies. Therefore, flies were exposed to MA (5mM) or MMA (5mM) and concomitantly treated with CA (1.39μg/mL), CAF (1.27μg/mL) or CA + CAF for 10days for survival, and for 4days for behavioural and biochemical assays. CA, CAF and CA + CAF treatments completely abolished the mortality associated with either MMA or MA exposure. Moreover, CA and CAF, either alone or combined, completely abolished behavioural changes, and completely protect against changes in thiobarbituric acid reactive substances (TBARS) levels, catalase (CAT) activity and MTT reduction ability, associated with MA or MMA exposure. In turn, CAF restored SOD activity in the head of flies exposed to MA or MMA. However, CA and CAF (either alone or combined) significantly decreased acetylcholinesterase (AChE) activity per se, while CAF alone protected from changes in AChE activity (in head tissue) associated with MA or MMA. Finally, CA and/or CAF were able to protect from a decrease in glucose and triglyceride levels associated with both MA and MMA exposures in haemolymph. Together, our data confirm the hypothesis that supplementation with CA and/or CAF offers protection against detrimental changes associated with MMA or MA exposure in flies, being responsible, at least in part, for the protective effect of I. paraguariensis crude extract which was reported previously.

Long-Term Tolerance Acquisition and Changes in Acetylcholinesterase Activity in Three Cladoceran Species After a 48-H Pulsed Exposure to Pirimicarb

We investigated (1) whether rapid acquisition of tolerance to pirimicarb would develop in three cladocerans (Daphnia magna, Scapholeberis kingi, and Ceriodaphnia cornuta) after short-term exposure and whether this tolerance was maintained in their descendants over four generations; (2) whether tolerance implies fitness costs, and whether these costs quantitatively correlated with tolerance levels; and (3) how AChE activity and AChE mRNA levels were altered by short-term exposure to pirimicarb. After 48 h of exposure to 0, 1.3, 2.5, 5.0, 10.0, 20.0, and 40.0 μg/L pirimicarb only in F0 generation, the surviving cladocerans in the concentrations (0, 1.3, 2.5, 5.0, 10.0 μg/L) were subsequently kept for additional three generations (F1, F2, and F3) in the absence of pirimicarb. Among the three tested cladocerans, the EC50 value (50% effective concentration for 48 h exposure, using immobility as the endpoint) of only C. cornuta increased significantly. The increased tolerance in C. cornuta was retained in F1, F2, and F3. In C. cornuta, AChE activity and AChE mRNA levels in F0 decreased significantly, but these values in F1 were comparable to those in the controls, suggesting these changes may be related to the tolerance. Direct exposure of F0 C. cornuta to 2.5 μg/L or 5.0 μg/L pirimicarb induced a decrease in intrinsic population growth rate. However, this effect disappeared as soon as exposure was removed in F1. Thus, tolerance to pirimicarb, as observed in C. cornuta, involves no fitness cost. Our findings will contribute to clarifying adaptation of aquatic organisms to chemicals.