https://observatorio.fm.usp.br/handle/OPI/11787
Title: | Bimodal Effect of Lithium Plasma Levels on Hippocampal Glutamate Concentrations in Bipolar II Depression: A Pilot Study |
Authors: | ZANETTI, Marcus V.; OTADUY, Maria C.; SOUSA, Rafael T. de; GATTAZ, Wagner F.; BUSATTO, Geraldo F.; LEITE, Claudia C.; MACHADO-VIEIRA, Rodrigo |
Citation: | INTERNATIONAL JOURNAL OF NEUROPSYCHOPHARMACOLOGY, v.18, n.6, 2015 |
Abstract: | Background: The hippocampus has been highly implicated in the pathophysiology of bipolar disorder (BD). Nevertheless, no study has longitudinally evaluated hippocampal metabolite levels in bipolar depression under treatment with lithium. Methods: Nineteen medication-free BD patients (78.9% treatment-naive and 73.7% with BD type II) presenting an acute depressive episode and 17 healthy controls were studied. Patients were treated for 6 weeks with lithium in an open-label trial. N-acetyl aspartate (NAA), creatine, choline, myo-Inositol, and glutamate levels were assessed in the left hippocampus before (week 0) and after (week 6) lithium treatment using 3T proton magnetic resonance spectroscopy (1H-MRS). The metabolite concentrations were estimated using internal water as reference and voxel segmentation for partial volume correction. Results: At baseline, acutely depressed BD patients and healthy controls exhibited similar hippocampal metabolites concentrations, with no changes after 6 weeks of lithium monotherapy. A significant correlation between antidepressant efficacy and increases in NAA concentration over time was observed. Also, there was a significant positive correlation between the changes in glutamate concentrations over follow-up and plasma lithium levels at endpoint. Mixed effects model analysis revealed a bimodal effect of lithium plasma levels in hippocampal glutamate concentrations: levels of 0.2 to 0.49 mmol/L (n=9) were associated with a decrease in glutamate concentrations, whereas the subgroup of BD subjects with ""standard"" lithium levels (>= 0.50 mmol/L; n = 10) showed an overall increase in glutamate concentrations over time. Conclusions: These preliminary results suggest that lithium has a bimodal action in hippocampal glutamate concentration depending on the plasma levels. |
Appears in Collections: | Artigos e Materiais de Revistas Científicas - FM/MDR Artigos e Materiais de Revistas Científicas - FM/MPS Artigos e Materiais de Revistas Científicas - HC/InRad Artigos e Materiais de Revistas Científicas - HC/IPq Artigos e Materiais de Revistas Científicas - LIM/21 Artigos e Materiais de Revistas Científicas - LIM/27 Artigos e Materiais de Revistas Científicas - LIM/44 |
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art_ZANETTI_Bimodal_Effect_of_Lithium_Plasma_Levels_on_Hippocampal_2015.PDF Restricted Access | publishedVersion (English) | 1.25 MB | Adobe PDF | View/Open Request a copy |
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