RAFAEL AUGUSTO TEIXEIRA DE SOUSA

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LIM/27 - Laboratório de Neurociências, Hospital das Clínicas, Faculdade de Medicina

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  • article 33 Citação(ões) na Scopus
    Increased Brain Lactate During Depressive Episodes and Reversal Effects by Lithium Monotherapy in Drug-Naive Bipolar Disorder A 3-T H-1-MRS Study
    (2017) MACHADO-VIEIRA, Rodrigo; ZANETTI, Marcus V.; OTADUY, Maria C.; SOUSA, Rafael T. De; SOEIRO-DE-SOUZA, Marcio G.; COSTA, Alana C.; CARVALHO, Andre F.; LEITE, Claudia C.; BUSATTO, Geraldo F.; ZARATE JR., Carlos A.; GATTAZ, Wagner F.
    Objective: Mitochondrial dysfunction and energy metabolism impairment are key components in the pathophysiology of bipolar disorder (BD) and may involve a shift from aerobic to anaerobic metabolism. Measurement of brain lactate in vivo using protonmagnetic resonance spectroscopy (H-1-MRS) represents an important tool to evaluate mitochondrial and metabolic dysfunction during mood episodes, as well as to monitor treatment response. To date, very few studies have quantified brain lactate in BD. In addition, no study has longitudinally evaluated lactate using H-1-MRS during depressive episodes or its association with mood stabilizer therapy. This study aimed to evaluate cingulate cortex (CC) lactate using 3-T H-1-MRS during acute depressive episodes in BD and the possible effects induced by lithium monotherapy. Methods: Twenty medication-free outpatients with short length of BD (80% drug-naive) in a current major depressive episode were matched with control subjects. Patients were treated for 6 weeks with lithium monotherapy at therapeutic doses in an open-label trial (blood level, 0.48 +/- 0.19 mmol/L). Cingulate cortex lactate was measured before (week 0) and after lithium therapy (week 6) using H-1-MRS. Antidepressant efficacy was assessed with the 21-item Hamilton Depression Rating Scale as the primary outcome. Results: Subjects with BD depression showed a significantly higher CC lactate in comparison to control subjects. Furthermore, a significant decrease in CC lactate was observed after 6 weeks of lithium treatment compared with baseline (P = 0.002). CC Lactate levels was associated with family history of mood disorders and plasma lithium levels. Conclusions: This is the first report of increased CC lactate in patients with bipolar depression and lower levels after lithium monotherapy for 6 weeks. These findings indicate a shift to anaerobic metabolism and a role for lactate as a state marker during mood episodes. Energy and redox dysfunction may represent key targets for lithium's therapeutic actions.
  • article 11 Citação(ões) na Scopus
    Epistasis between COMT Val(158)Met and DRD3 Ser(9)Gly polymorphisms and cognitive function in schizophrenia: genetic influence on dopamine transmission
    (2015) LOCH, Alexandre A.; BILT, Martinus T. van de; BIO, Danielle S.; PRADO, Carolina M. do; SOUSA, Rafael T. de; VALIENGO, Leandro L.; MORENO, Ricardo A.; ZANETTI, Marcus V.; GATTAZ, Wagner F.
    Objective: To assess the relationship between cognitive function, a proposed schizophrenia endophenotype, and two genetic polymorphisms related to dopamine function, catechol-O-methyl transferase (COMT) Val(158)Met and dopamine receptor 3 (DRD3) Ser(9)Gly. Methods: Fifty-eight outpatients with schizophrenia/schizoaffective disorder and 88 healthy controls underwent neurocognitive testing and genotyping. Analyses of covariance (ANCOVAs) using age, sex, and years of education as covariates compared cognitive performance for the proposed genotypes in patients and controls. ANCOVAs also tested for the epistatic effect of COMT and DRD3 genotype combinations on cognitive performance. Results: For executive functioning, COMT Val/Val patients performed in a similar range as controls (30.70-33.26 vs. 35.53-35.67), but as COMT Met allele frequency increased, executive functioning worsened. COMT Met/Met patients carrying the DRD3 Ser/Ser genotype performed poorest (16.184 vs. 27.388-31.824). Scores of carriers of this COMT/DRD3 combination significantly differed from all DRD3 Gly/Gly combinations (p < 0.05), from COMT Val/Met DRD3 Ser/Gly (p = 0.02), and from COMT Val/Val DRD3 Ser/Ser (p = 0.01) in patients. It also differed significantly from all control scores (p < 0.001). Conclusion: Combined genetic polymorphisms related to dopamine neurotransmission might influence executive function in schizophrenia. Looking at the effects of multiple genes on a single disease trait (epistasis) provides a comprehensive and more reliable way to determine genetic effects on endophenotypes.
  • article 12 Citação(ões) na Scopus
    Lithium efficacy in bipolar depression with flexible dosing: A six-week, open-label, proof-of-concept study
    (2014) MACHADO-VIEIRA, Rodrigo; ZANETTI, Marcus V.; SOUSA, Rafael T. De; SOEIRO-DE-SOUZA, Marcio G.; MORENO, Ricardo A.; BUSATTO, Geraldo F.; GATTAZ, Wagner F.
    Lithium has a narrow therapeutic index with a subtle balance between effectiveness and adverse effects. Current guidelines recommend the use of lithium as a treatment for acute bipolar depression; however, the therapeutic range for the treatment has not been fully defined. Recently, the adjunctive lower lithium dose in bipolar depression has revealed potential efficacy; however, no study has investigated it predominantly in monotherapy. In this open-label, proof-of-concept study, 31 individuals with bipolar disorder during a depressive episode were randomized and 29 were followed up for six weeks with flexible lithium dosing. All subjects had a 21-item Hamilton Rating Scale for Depression (HAM-D) score of >= 18 at baseline. Subjects were divided into two groups, with higher (Li >= 0.5 mEq/l) or lower (Li <0.5 mEq/l) blood lithium levels. Response and remission rates were evaluated using the HAM-D scores. Following 6 weeks of lithium treatment, the remission rate for all patients was 62.0%. The plasma lithium levels did not impact the clinical response. However, subjects with higher blood lithium levels had an increased prevalence of nausea, restlessness, headaches and cognitive complaints. The results indicate that the lithium dose for the treatment of bipolar depression in an individual should be based on the clinical efficacy and side-effects. In the context of personalized psychiatric treatments, it is necessary to evaluate the therapeutic action of lithium with individual regimens in order to develop more tolerable and effective treatment approaches.
  • article 13 Citação(ões) na Scopus
    Regulation of leukocyte tricarboxylic acid cycle in drug-naive Bipolar Disorder
    (2015) SOUSA, Rafael T. de; STRECK, Emilio L.; FORLENZA, Orestes V.; BRUNONI, Andre R.; ZANETTI, Marcus V.; FERREIRA, Gabriela K.; DINIZ, Breno S.; PORTELA, Luis V.; CARVALHO, Andre F.; ZARATE JR., Carlos A.; GATTAZ, Wagner F.; MACHADO-VIEIRA, Rodrigo
    Several lines of evidence suggest a role for mitochondrial dysfunction in the pathophysiology of bipolar disorder (BD). The tricarboxylic acid cycle (TCA cycle) is fundamental for mitochondrial energy production and produces substrates used in oxidative phosphorylation by the mitochondrial electron transport chain. The activity of the key TCA cycle enzymes citrate synthase, malate dehydrogenase, and succinate dehydrogenase has never been evaluated in BD. In the present study, these enzymes were assayed from leukocytes of drug-naive BD patients in a major depressive episode (n = 18) and compared to 24 age-matched healthy controls. Drug-naive BD patients did not show differences in activities of citrate synthase (p = 0.79), malate dehydrogenase (p = 0.17), and succinate dehydrogenase (p = 0.35) compared with healthy controls. No correlation between any TCA cycle enzyme activity and severity of depressive symptoms was observed. Overall, these data suggest that the activities of the TCA cycle enzymes are not altered in major depressive episodes of recent-onset BD, which may support the concept of illness staging and neuroprogression in BD.
  • article 34 Citação(ões) na Scopus
    Genetic Studies on the Tripartite Glutamate Synapse in the Pathophysiology and Therapeutics of Mood Disorders
    (2017) SOUSA, Rafael T. de; LOCH, Alexandre A.; CARVALHO, Andre F.; BRUNONI, Andre R.; HADDAD, Marie Reine; HENTER, Ioline D.; ZARATE JR., Carlos A.; MACHADO-VIEIRA, Rodrigo
    Both bipolar disorder (BD) and major depressive disorder (MDD) have high morbidity and share a genetic background. Treatment options for these mood disorders are currently suboptimal for many patients; however, specific genetic variables may be involved in both pathophysiology and response to treatment. Agents such as the glutamatergic modulator ketamine are effective in treatment-resistant mood disorders, underscoring the potential importance of the glutamatergic system as a target for improved therapeutics. Here we review genetic studies linking the glutamatergic system to the pathophysiology and therapeutics of mood disorders. We screened 763 original genetic studies of BD or MDD that investigated genes encoding targets of the pathway/mediators related to the so-called tripartite glutamate synapse, including pre- and post-synaptic neurons and glial cells; 60 papers were included in this review. The findings suggest the involvement of glutamate-related genes in risk for mood disorders, treatment response, and phenotypic characteristics, although there was no consistent evidence for a specific gene. Target genes of high interest included GRIA3 and GRIK2 (which likely play a role in emergent suicidal ideation after antidepressant treatment), GRIK4 (which may influence treatment response), and GRM7 (which potentially affects risk for mood disorders). There was stronger evidence that glutamate-related genes influence risk for BD compared with MDD. Taken together, the studies show a preliminary relationship between glutamate-related genes and risk for mood disorders, suicide, and treatment response, particularly with regard to targets on metabotropic and ionotropic receptors.
  • article 44 Citação(ões) na Scopus
    Lithium increases platelet serine-9 phosphorylated GSK-3 beta levels in drug-free bipolar disorder during depressive episodes
    (2015) SOUSA, Rafael T. de; ZANETTI, Marcus V.; TALIB, Leda L.; SERPA, Mauricio H.; CHAIM, Tiffany M.; CARVALHO, Andre F.; BRUNONI, Andre R.; BUSATTO, Geraldo F.; GATTAZ, Wagner E.; MACHADO-VIEIRA, Rodrigo
    Background: Glycogen synthase kinase-3 beta (GSK3 beta) is an intracellular enzyme directly implicated in several neural processes relevant to bipolar disorder (BD) pathophysiology. GSK3 beta is also an important target for lithium and antidepressants. When phosphorylated at serine-9, GSK3 beta becomes inactive. Few studies evaluated serine-9 phosphorylated GSK3 beta(phospho-GSK3 beta) levels in BD subjects in vivo and no study has assessed it specifically in bipolar depression. Also, the effect of lithium monotherapy on GSK3 beta has never been studied in humans. Methods: In 27 patients with bipolar depression, total GSK3 beta and phospho-GSK3 beta were assessed in platelets by enzyme immunometric assay. Subjects were evaluated before and after 6 weeks of lithium treatment at therapeutic levels. Healthy subjects (n = 22) were used as a control group. Results: No differences in phospho-GSK3 beta or total GSK3 beta were observed when comparing drug-free BD subjects in depression and healthy controls. Baseline HAM-D scores were not correlated with phospho GSK3 beta and total GSK3 beta levels. From baseline to endpoint, lithium treatment inactivated GSK3 beta by significantly increasing phospho-GSK3 beta levels (p = 0.010). Clinical improvement (baseline HAM-D endpoint HAM-D) negatively correlated with the increase in phospho-GSK3 beta (p = 0.03). Conclusion: The present results show that lithium inactivates platelet GSK3 beta in BD during mood episodes. No direct association with pathophysiology of BD was observed. Further studies are needed to clarify the role of GSK3 beta as a key biomarker in BD and its association with treatment response as well as the relevance of GSK3 beta in other neuropsychiatric disorders and as a new therapeutic target per se.
  • article 101 Citação(ões) na Scopus
    Lithium increases plasma brain-derived neurotrophic factor in acute bipolar mania: A preliminary 4-week study
    (2011) SOUSA, Rafael T. de; BILT, Martinus T. van de; DINIZ, Breno S.; LADEIRA, Rodolfo B.; PORTELA, Luis V.; SOUZA, Diogo O.; FORLENZA, Orestes V.; GATTAZ, Wagner F.; MACHADO-VIEIRA, Rodrigo
    Several studies have suggested an important role for brain-derived neurotrophic factor (BDNF) in the pathophysiology and therapeutics of bipolar disorder (BPD). The mechanisms underlying the therapeutic effects of lithium in BPD seem to involve a direct regulation of neurotrophic cascades. However, no clinical study evaluated the specific effects of lithium on BDNF levels in subjects with BPD. This study aims to investigate the effects of lithium monotherapy on BDNF levels in acute mania. Ten subjects with bipolar I disorder in a manic episode were evaluated at baseline and after 28 days of lithium therapy. Changes in plasma BDNF levels and Young Mania Rating Scale (YMRS) scores were analyzed. A significant increase in plasma BDNF levels was observed after 28 days of therapy with lithium monotherapy (510.9 +/- 127.1 pg/mL) compared to pre-treatment (406.3 +/- 69.5 pg/mL) (p = 0.03). Although it was not found a significant association between BDNF levels and clinical improvement (YMRS), 87% of responders presented an increase in BDNF levels after treatment with lithium. These preliminary data showed lithium's direct effects on BDNF levels in bipolar mania, suggesting that short-term lithium treatment may activate neurotrophic cascades. Further studies with larger samples and longer period may confirm whether this biological effect is involved in the therapeutic efficacy of lithium in BPD.
  • article 4 Citação(ões) na Scopus
    The role of lithium treatment on comorbid anxiety symptoms in patients with bipolar depression
    (2022) JONES, Gregory; RONG, Carola; VECERA, Courtney M.; I, Christopher Gurguis; CHUDAL, Roshan; KHAIROVA, Rushaniya; LEUNG, Edison; RUIZ, Ana C.; SHAHANI, Lokesh; V, Marcus Zanetti; SOUSA, Rafael T. de; BUSATTO, Geraldo; SOARES, Jair; GATTAZ, Wagner F.; MACHADO-VIEIRA, Rodrigo
    Background: Comorbid anxiety is pervasive and carries an immense psychosocial burden for patients with bipolar disorder. Despite this, trials reporting anxiety-related outcomes in this population are uncommon, particularly with regards to monotherapies.Methods: Patients (n = 31) with both bipolar I or II disorder in current depressive episodes were enrolled in a sixweek, open-label, single-center trial assessing the efficacy of lithium monotherapy in treating symptoms depression and comorbid anxiety. Patients were mostly medication-free and lithium-naive at baseline.Results: Significant improvements in depression (HAM-D) and anxiety (HAM-A) were observed at the six-week endpoint, with remission and response rates greater than 50%. There was a positive correlation between endpoint HAM-A scores and HAM-D scores, r = 0.80, (p < 0.01). Improvements were realized at low serum lithium concentrations (0.49 +/- 0.20 mEq/L). Limitations: Lack of placebo control and small sample size warrants validation in larger randomized studies.Conclusions: Taken in the context of prior evidence, lithium may have an important role in treating comorbid anxiety in bipolar disorder, both as adjunct and monotherapy. Lower doses of lithium may provide equivalent efficacy and enhance tolerability and compliance.
  • article 10 Citação(ões) na Scopus
    Early improvement of psychotic symptoms with lithium monotherapy as a predictor of later response in mania
    (2012) SOUSA, Rafael T. de; BUSNELLO, Joao V.; FORLENZA, Orestes V.; ZANETTI, Marcus V.; SOEIRO-DE-SOUZA, Marcio G.; BILT, Martinus T. van de; MORENO, Ricardo A.; ZARATE JR., Carlos A.; GATTAZ, Wagner F.; MACHADO-VIEIRA, Rodrigo
    Although lithium has been the first line agent in the treatment of bipolar disorder (BD), few studies have evaluated lithium's efficacy in mania with psychosis and its association with later response. Furthermore, given the widespread concern about antipsychotic side effects, answering a question about whether lithium alone can manage to treat both psychotic and non-psychotic mania seems a very relevant one. The present study addresses the antipsychotic efficacy of lithium monotherapy in acute mania and early improvement of psychotic symptoms as a predictor of later response of manic symptoms. Forty-six patients presenting a manic episode (32 with psychotic features and 14 subjects without psychotic features) were treated for 4 weeks with lithium monotherapy and evaluated weekly using the Young Mania Rating Scale (YMRS). Subjects with rapid cycling, substance abuse/dependence, or mixed episodes were excluded. The overall antimanic efficacy of lithium in psychosis vs. non-psychosis groups was evaluated. In addition, early improvement of psychotic symptoms and its prediction of subsequent response (>50% decrease in total YMRS scores) or remission were evaluated. Lithium showed a similar efficacy in both psychosis and non-psychosis mania. Early improvement of psychotic symptoms was associated with clinical response and remission at endpoint.
  • article 30 Citação(ões) na Scopus
    Elevated neurotrophin-3 and neurotrophin 4/5 levels in unmedicated bipolar depression and the effects of lithium
    (2015) LOCH, Alexandre A.; ZANETTI, Marcus V.; SOUSA, Rafael T. de; CHAIM, Tiffany M.; SERPA, Mauricio H.; GATTAZ, Wagner F.; TEIXEIRA, Antonio L.; MACHADO-VIEIRA, Rodrigo
    Background: Bipolar disorder (BD) has been associated with diverse abnormalities in neural plasticity and cellular resilience. Neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5) support synaptic neuronal survival and differentiation. NT-3 and NT-4/5 levels were found to be altered in BD, potentially representing a physiological response against cellular stress. However, the use of psychopharmacological agents and heterogeneous mood states may constitute important biases in such studies. Thus, we aimed to assess NT-3 and NT-4/5 levels in medication-free BD type I or II individuals in a current depressive episode, before and after 6weeks of lithium monotherapy and matched with healthy controls. Methods: Twenty-three patients with BD type I or II during a depressive episode and 28 healthy controls were studied. Patients were required to have a 21-item Hamilton Depression Rating Scale score >= 18 and had not undergone any psychopharmacological treatment for at least 6 weeks prior to study entry. Patients were treated with lithium for 6 weeks and plasma NT-3 and NT-4/5 levels were determined at baseline and end point using ELISA method. Results: Baseline plasma levels of both NT-3 and NT-4/5 were significantly increased in acutely depressed BD subjects in comparison to healthy controls (p = 0.040 and 0.039, respectively). The NT-3 and NT-4/5 levels did not significantly change after lithium treatment. NT-3 and NT-4/5 levels were positively correlated to illness duration in BD (p = 0.032 and 0.034, respectively). Conclusion: Our findings suggest that NT-3 and NT-4/5 levels are increased in the depressive phase of BD, which seems directly associated with illness duration. The increased levels of NT-3 and NT-4/5 may underlie a biological response to cellular stress associated with the course of BD.