Júlia Niehues da Cruz

Behavioral interactions of simvastatin and fluoxetine in tests of anxiety and depression

Simvastatin inhibits 3-hydroxy-3-methylglutaryl CoA reductase, the rate-limiting enzyme in the cholesterol biosynthetic pathway, and is widely used to control plasma cholesterol levels and prevent cardiovascular disease. However, emerging evidence indicates that the beneficial effects of simvastatin extend to the central nervous system. The effects of simvastatin combined with fluoxetine provide an exciting and potential paradigm to decreased anxiety and depression. Thus, the present paper investigates the possibility of synergistic interactions between simvastatin and fluoxetine in models of anxiety and depression. We investigated the effects of subchronically administered simvastatin (1 or 10 mg/kg/day) combined with fluoxetine (2 or 10 mg/kg) at 24, 5, and 1 hour on adult rats before conducting behavioral tests. The results indicate that simvastatin and/or fluoxetine treatment reduces anxiety-like behaviors in the elevated plus-maze and open-field tests. Our results showed that simvastatin and/or fluoxetine induced a significant increase in the swimming activity during the forced swimming test (antidepressant effect), with a concomitant increase in climbing time in simvastatin-treated animals only (noradrenergic activation). We hypothesize that anxiolytic and antidepressant effects of simvastatin and/or fluoxetine produce their behavioral effects through similar mechanisms and provide an important foundation for future preclinical research.

Incidência de delirium durante a internação em unidade de terapia intensiva em pacientes pré-tratados com estatinas no pós-operatório de cirurgia cardíaca

OBJECTIVE To determine the association between the preoperative administration of statins and postoperative delirium in a prospective cohort of patients undergoing cardiac surgery. METHODS All adult patients who were admitted to the intensive care unit following cardiac surgery between January and June 2011 were included. Delirium was screened during the postoperative period using the Confusion Assessment Method for Intensive Care Unit (CAM-ICU) and Intensive Care Delirium Screening Checklist (ICDSC). RESULTS A total of 169 patients underwent elective cardiac surgery, and 40.2% of the patients were treated preoperatively with statins. Delirium was identified using the CAM-ICU in 14.9% of patients not taking preoperative statins in comparison with 11.8% of the patients taking statins (p = 0.817). Using the ICDSC, delirium was identified in 18.8% of patients not taking statins in comparison with 10.3% of the patients taking statins (p = 0.191). CONCLUSION The use of preoperative statins is not correlated with postoperative delirium in patients undergoing cardiac surgery.

Antioxidant effect of simvastatin throught oxidative imbalance caused by lisdexamfetamine dimesylate.

The present study aims to directly investigate the behavioral and antioxidant effects of simvastatin in a model of bipolar mania induced by lisdexamfetamine dimesylate. Wistar rats were treated for 30 days with simvastatin. On the 24th day after the start of treatment, each rat was administered lisdexamfetamine dimesylate for 7 days. The results suggest that simvastatin combined with lisdexamfetamine dimesylate induced a significant increased locomotion and lisdexamfetamine dimesylate administration causes an oxidative imbalance determined by an increment in lipid peroxidation, protein oxidation and alterations in the activities of antioxidant enzymes in brain areas; moreover, in the presence of simvastatin, most of these effects were prevented. These findings contribute to a better understanding of the critical roles of lisdexamfetamine dimesylate in the treatment of neuropsychiatric disorders, associated with increased oxidative stress and changes in antioxidant enzymatic defense. In view of the central role played by lisdexamfetamine dimesylate, the established antioxidant effect of simvastatin therapy is of major interest.

Guanidinoacetate alters antioxidant defenses and butyrylcholinesterase activity in the blood of rats

Deficiency of guanidinoacetate methyltransferase, the first described creatine biosynthesis defect, leads to depletion of creatine and phosphocreatine, and accumulation of guanidinoacetate (GAA) in brain and body fluids. The present study aimed to investigate the influence of GAA on the activities of antioxidant enzymes, as well as on thiobarbituric acid-reactive substances (TBARS) and butyrylcholinesterase (BuChE) activity in the blood of rats. Results showed that GAA enhanced the activities of catalase (CAT) and glutathione peroxidase (GSH-Px) in the erythrocytes and BuChE activity. In addition, GAA enhanced TBARS levels in the plasma. Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), GSH (glutathione) and L-NAME (NG-nitro-L-arginine methyl ester) addition prevented the majority of alterations in oxidative stress parameters and the increase of BuChE activity that were caused by GAA. Data suggest that GAA alters antioxidant defenses and induces lipid peroxidation in the blood, as well altering BuChE activity. However, in the presence of trolox, GSH and L-NAME some of these alterations in oxidative stress and BuChE activity were prevented. Our findings lend support to a potential therapeutic strategy for this condition, which may include the use of appropriate antioxidants for ameliorating the damage caused by GAA.