Maria Rosa Chitolina Schetinger

Resveratrol prevents memory deficits and the increase in acetylcholinesterase activity in streptozotocin-induced diabetic rats

The objective of the present study was to investigate the effect of the administration of resveratrol (RV) on memory and on acetylcholinesterase (AChE) activity in the cerebral cortex, hippocampus, striatum, hypothalamus, cerebellum and blood in streptozotocin-induced diabetic rats. The animals were divided into six groups (n=6-13): Control/saline; Control/RV 10 mg/kg; Control/RV 20 mg/kg; Diabetic/saline; Diabetic/RV 10 mg/kg; Diabetic/RV 20 mg/kg. One day after 30 days of treatment with resveratrol the animals were submitted to behavioral tests and then submitted to euthanasia and the brain structures and blood were collected. The results showed a decrease in step-down latency in diabetic/saline group. Resveratrol (10 and 20 mg/kg) prevented the impairment of memory induced by diabetes. In the open field test, no significant differences were observed between the groups. In relation to AChE activity, a significant increase in diabetic/saline group (P<0.05) was observed in all brain structures compared to control/saline group. However, AChE activity decreased significantly in control/RV10 and control/RV20 (P<0.05) groups in cerebral cortex, hippocampus and striatum, while no significant differences were observed in diabetic/RV10 and diabetic/RV20 groups in all brain structures compared to control/saline group. Blood AChE activity increased significantly in diabetic/saline group (P<0.05) decreased in control/RV10, control/RV20 and diabetic/RV20 groups (P<0.05) compared to control/saline group. In conclusion, the present findings showed that treatment with resveratrol prevents the increase in AChE activity and consequently memory impairment in diabetic rats, demonstrating that this compound can modulate cholinergic neurotransmission and consequently improve cognition.

Association between ischemia-modified albumin, lipids and inflammation biomarkers in patients with hypercholesterolemia.

OBJECTIVES The aim of this study was to evaluate the association between ischemia-modified albumin (IMA), lipids and inflammation biomarkers in patients with hypercholesterolemia, and the possible involvement of IMA in atheromatous plaque development and oxidative stress. DESIGN AND METHODS Glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, oxidized LDL (ox-LDL), ox-LDL autoantibodies, high-sensitivity C reactive protein (hs-CRP), and IMA were measured in 37 subjects with hypercholesterolemia and 37 controls. RESULTS Total cholesterol, LDL cholesterol, triglycerides, ox-LDL, ox-LDL autoantibodies, hs-CRP, and IMA were higher in the hypercholesterolemia group, and HDL cholesterol levels were lower in this group. We observed significant correlations between IMA and total cholesterol, LDL cholesterol, ox-LDL antibodies, and hs-CRP levels. Significant correlations were also observed between hs-CRP and total cholesterol, HDL cholesterol, LDL cholesterol, ox-LDL, ox-LDL autoantibodies, and triglycerides. CONCLUSIONS Hypercholesterolemia is associated with an increase in inflammatory and oxidative stress biomarkers, and it also reduces the capacity of albumin to bind cobalt owing to ischemia, resulting in an increased IMA. IMA formation appears to be associated with oxidative stress and atheromatous plaque development.

N-acetylcysteine prevents memory deficits, the decrease in acetylcholinesterase activity and oxidative stress in rats exposed to cadmium

The present study investigated the effect of the administration of N-acetylcysteine (NAC), on memory, on acetylcholinesterase (AChE) activity and on lipid peroxidation in different brain structures in cadmium (Cd)-exposed rats. The rats received Cd (2 mg/kg) and NAC (150 mg/kg) by gavage every other day for 30 days. The animals were divided into four groups (n=12-13): control/saline, NAC, Cd, and Cd/NAC. The results showed a decrease in step-down latency in the Cd-group, but NAC reversed the impairment of memory induced by Cd intoxication. Rats exposed to Cd and/or treated with NAC did not demonstrate altered shock sensitivity. Decreased AChE activity was found in hippocampus, cerebellum and hypothalamus in the Cd-group but NAC reversed this effect totally or partially while in cortex synaptosomes and striatum there was no alteration in AChE activity. An increase in TBARS levels was found in hippocampus, cerebellum and hypothalamus in the Cd-group and NAC abolished this effect while in striatum there was no alteration in TBARS levels. Urea and creatinine levels were increased in serum of Cd-intoxicated rats, but NAC was able to abolish these undesirable effects. The present findings show that treatment with NAC prevented the Cd-mediated decrease in AChE activity, as well as oxidative stress and consequent memory impairment in Cd-exposed rats, demonstrating that this compound may modulate cholinergic neurotransmission and consequently improve cognition. However, it is necessary to note that the mild renal failure may be a contributor to the behavioral impairment found in this investigation.

Measurement of oxidative stress and antioxidant status in acute lymphoblastic leukemia patients

OBJECTIVES To evaluate the oxidative status and antioxidant defense in patients with acute lymphoblastic leukemia (ALL). DESIGN AND METHODS We measured concentrations of plasmatic thiobarbituric acid reactive substances (TBARS), serum protein carbonylation, whole blood catalase (CAT) and superoxide dismutase (SOD) activities, as well as the plasmatic and erythrocyte thiol levels and serum vitamin E concentration. This study was performed on 80 children with ALL divided into 4 groups: just diagnosed, remission induction, remission maintenance and out-of-treatment. RESULTS TBARS levels and serum protein carbonylation were higher in ALL patients than in controls and reduced levels of antioxidants were found in these patients. CONCLUSION These findings may indicate a possible link between decreased antioxidants and increased levels of cells alterations due to oxidative damage, supporting the idea that there is a persistence of oxidative stress in acute lymphoblastic leukemia.

New Benzodiazepines Alter Acetylcholinesterase and ATPDase Activities

This study examines the effect of new 1,5 benzodiazepines on acetylcholinesterase (AChE) and ATPDase (apyrase) activities from cerebral cortex of adult rats. Simultaneously, the effects of the classical 1,4-benzodiazepine on these enzymes were also studied for comparative purpose. The compounds 2-trichloromethyl-4-phenyl-3H-1,5-benzodiazepin and 2-trichloromethyl-4-(p-methyl-phenyl)-3H-1,5-benzodiazepin significantly inhibited acetylcholinesterase activity (p < 0.01) when tested in the range of 0.18–0.35 mM. The inhibition caused by these two new benzodiazepines was noncompetitive in nature. Similarly, at concentrations ranging from 0.063 to 0.25 mM, the 1,5 benzodiazepines inhibited ATP and ADP hydrolysis by synaptosomes from cerebral cortex (p < 0.01). However, the inhibition of nucleotide hydrolysis was uncompetitive in nature. Our results suggest that, although diazepam and the new benzodiazepines have chemical differences, they both presented an inhibitory effect on acetylcholinesterase and ATPDase activities.

Differential Macrophage Activation Alters the Expression Profile of NTPDase and Ecto-5′-Nucleotidase

Macrophages are key elements in the inflammatory process, whereas depending on the micro-environmental stimulation they exhibit a pro-inflammatory (classical/M1) or an anti-inflammatory/reparatory (alternative/M2) phenotype. Extracellular ATP can act as a danger signal whereas adenosine generally serves as a negative feedback mechanism to limit inflammation. The local increase in nucleotides communication is controlled by ectonucleotidases, such as members of the ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) family and ecto-5′-nucleotidase/CD73 (ecto-5′-NT). In the present work we evaluated the presence of these enzymes in resident mice M1 (macrophages stimulated with LPS), and M2 (macrophages stimulated with IL-4) macrophages. Macrophages were collected by a lavage of the mice (6–8 weeks) peritoneal cavity and treated for 24 h with IL-4 (10 ng/mL) or LPS (10 ng/mL). Nitrite concentrations were measured using the Greiss reaction. Supernatants were harvested to determine cytokines and the ATPase, ADPase and AMPase activities were determined by the malachite green method and HPLC analysis. The expression of selected surface proteins was evaluated by flow cytometry. The results reveal that M1 macrophages presented a decreased ATP and AMP hydrolysis in agreement with a decrease in NTPDase1, -3 and ecto-5′-nucleotidase expression compared to M2. In contrast, M2 macrophages showed a higher ATP and AMP hydrolysis and increased NTPDase1, -3 and ecto-5′-nucleotidase expression compared to M1 macrophages. Therefore, macrophages of the M1 phenotype lead to an accumulation of ATP while macrophages of the M2 phenotype may rapidly convert ATP to adenosine. The results also showed that P1 and P2 purinoreceptors present the same mRNA profile in both phenotypes. In addition, M2 macrophages, which have a higher ATPase activity, were less sensitive to cell death. In conclusion, these changes in ectoenzyme activities might allow macrophages to adjust the outcome of the extracellular purinergic cascade in order to fine-tune their functions during the inflammatory set.

Cadmium toxicity causes oxidative stress and induces response of the antioxidant system in cucumber seedlings

In this study, the effects of cadmium (Cd) on lipid peroxidation, electrolyte leakage, protein oxidation, ascorbate peroxidase (APX; E.C. 1.11.1.11), catalase (CAT; E.C. 1.11.1.6) and superoxide dismutase (SOD; E.C. 1.15.1.1) activities, and ascorbic acid, non-protein thiol groups and total soluble protein contents in cucumber seedlings (Cucumis sativus L.) were investigated. Seedlings were grown in vitro in an agar-solidified substrate containing four Cd levels as CdCl2 (0, 100, 400, and 1000 µmol L-1) for 10 d. The lowest Cd level decreased the malondialdehyde concentration. Electrolyte leakage increased only at 1000 µmol Cd L-1, whereas protein oxidation and total soluble protein content were enhanced at 400 and 1000 µmol Cd L-1. Activity of APX was inhibited while the activities of CAT and SOD were increased at all Cd concentrations. Ascorbic acid was enhanced at 400 and 1000 µmol Cd L-1 whereas non-protein thiol groups were increased at all Cd supplies. The results evidence the importance of the enzymatic and non-enzymatic antioxidant system in response to cadmium toxicity in cucumber seedlings.

Antidepressants inhibit human acetylcholinesterase and butyrylcholinesterase activity

This study examines the effect of the antidepressants fluoxetine, sertraline and amitriptyline on cholinesterase (acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)) activities in human serum and erythrocyte membrane (ghost). The concentrations used range from 3 to 60 microM for fluoxetine and amitriptyline and 0.3 to 12 microM for sertraline. At the micromolar range concentration, different classes of antidepressants, including fluoxetine and sertraline (selective serotonin reuptake inhibitors (SSRIs)) and amitriptyline (tricyclic antidepressant) inhibited human serum cholinesterase. The order of inhibitory potency was sertraline>amitriptyline>>fluoxetine and the IC(50) values were 4.05, 9.43 and 62 microM, respectively. Analysis of kinetic data indicated that the inhibition caused by all the antidepressants was mixed in nature. At the micromolar range concentration, sertraline (60-120 microM) and amitriptyline (60-180 microM) inhibited human erythrocyte AChE. The order of inhibitory potency was sertraline>amitriptyline and the IC(50) values were 80 and 134 microM, respectively. Analysis of kinetic data indicated that the inhibition caused by all the antidepressants in AChE human erythrocyte membrane (ghost) was mixed in nature. The interaction of sertraline with the cholinesterase is labile since the removal of inhibitor by gel filtration recovered completely the enzyme activity. Our results demonstrate that the usual clinical antidepressants are inhibitors of the cholinesterases on human serum and erythrocyte membrane.

Oxidative stress versus antioxidant defenses in patients with acute myocardial infarction

Acute myocardial infarction (AMI) is a highly dynamic event, which is associated with increasing production of reactive oxygen species (ROS). The imbalance between ROS production and antioxidant defenses leads to the condition known as oxidative stress. The most widely recognized effect of increasing oxidative stress is the oxidation and damage of macromolecules, membranes, proteins, and DNA. Therefore, in this study we sought to evaluate oxidative stress and antioxidant defenses in patients with AMI. Lipid peroxidation, protein carbonyl levels, and enzymatic and nonenzymatic antioxidants were assessed in samples obtained from 40 AMI patients and 40 control patients. AMI was characterized by clinical, electrocardiographic, and laboratory criteria. The control group was divided into two groups of 20 patients: a control group with healthy patients and a risk group. Our results demonstrated an increase in substances reactive to thiobarbituric acid (TBARS) and carbonyl protein levels in the AMI and risk groups. In addition, a positive correlation was found between TBARS, carbonyl protein levels, and troponin I in AMI patients. Surprisingly, for the enzymatic antioxidant defenses, catalase and superoxide dismutase, we observed an increase in these parameters in the AMI and risk groups when compared with healthy patients. However, a decrease in nonenzymatic antioxidants such as vitamin C and vitamin E was observed in AMI patients when compared with the healthy group and the risk group. The increase in oxidative stress was probably a result of the elevation in ROS production due to the ischemic/reperfusion event that occurs in AMI, in addition to the decrease of nonenzymatic antioxidant defenses.

Oxidative stress in hypercholesterolemia and its association with Ala16Val superoxide dismutase gene polymorphism

OBJECTIVES To investigate the role of the oxidative stress and the antioxidant system as well as the influence of the manganese superoxide dismutase (Ala16Val) polymorphism on hypercholesterolemia. DESIGN AND METHODS Levels of glucose, lipid, high-sensitivity C reactive protein (hs-CRP), thiobarbituric acid reactive substances (TBARS), carbonyl protein, thiols, reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and vitamin C, vitamin E, as well as the presence of the manganese superoxide dismutase (Ala16Val) polymorphism were determined in 40 subjects with hypercholesterolemia and 40 controls. RESULTS Lipid profile, hs-CRP, glucose, TBARS, carbonyl protein, CAT, and vitamin E were significantly higher in subjects with hypercholesterolemia. In contrast, GSH and SOD were lower. TBARS, carbonyl protein, thiols, CAT, and vitamin E were significantly higher in hypercholesterolemic subjects with VV genotype for MnSOD, while GSH, SOD, and vitamin C were lower in these subjects. CONCLUSIONS We suggest an association between the genotypes of MnSOD, hypercholesterolemia, and oxidative stress biomarkers.