Mu-Hong Chen1, Wan-Chen Chang2, Ju-Wei Hsu3, Kai-Lin Huang3, Pei-Chi Tu4, Tung-Ping Su5, Cheng-Ta Li6, Wei-Chen Lin7, Ya-Mei Bai8. 1. Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, No. 201, Shih-Pai Road, Sec. 2, Taipei 11217, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan. Electronic address: kremer7119@gmail.com. 2. Department of Medical Research, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei 112 Taiwan. 3. Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, No. 201, Shih-Pai Road, Sec. 2, Taipei 11217, Taiwan. 4. Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, No. 201, Shih-Pai Road, Sec. 2, Taipei 11217, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei 112 Taiwan; Institute of Philosophy of Mind and Cognition, National Yang-Ming University, Taipei, Taiwan. Electronic address: peichitu@gmail.com. 5. Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, No. 201, Shih-Pai Road, Sec. 2, Taipei 11217, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei 112 Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan; Department of Psychiatry, Cheng Hsin General Hospital, Taipei, Taiwan. 6. Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, No. 201, Shih-Pai Road, Sec. 2, Taipei 11217, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan. 7. Department of Psychiatry, Taipei Veterans General Hospital, No. 201, Shih-Pai Road, Sec. 2, Taipei 11217, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan. 8. Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, No. 201, Shih-Pai Road, Sec. 2, Taipei 11217, Taiwan. Electronic address: ymbi@mail2000.com.tw.
Abstract
BACKGROUND: Gray matter volume reduction in specific brain regions, such as the prefrontal cortex, was found in patients with bipolar disorder and those with unipolar depression. However, few studies have directly compared gray matter volumes between bipolar disorder and unipolar depression. In addition, it is unknown whether proinflammatory cytokines play a role in the gray matter volume difference between bipolar disorder and unipolar depression. METHODS: Twenty-three patients with bipolar disorder and 23 with unipolar depression in a mildly ill state (Clinical Global Impression-Severity ≤ 3) were enrolled in our study. Each participant underwent structural magnetic resonance imaging and proinflammatory cytokines examination. Voxel-based morphometry was performed to investigate the gray matter volume difference between bipolar disorder and unipolar depression. Correlations of the proinflammatory cytokines and the gray matter volume difference were analyzed. RESULTS: Several brain regions, including the orbitofrontal cortex, lingual gyrus, inferior frontal cortex, middle frontal cortex, and planum polare, were significantly smaller in patients with bipolar disorder than in those with unipolar depression. These gray matter volume differences between bipolar disorder and unipolar depression were negatively correlated with soluble IL-6 receptor levels. DISCUSSION: Proinflammatory cytokines, especially IL-6, were associated with the gray matter volumes in bipolar disorder and unipolar depression. However, the complicated associations between proinflammatory cytokines, neurocognitive function, and gray matter volumes require further investigation.
BACKGROUND: Gray matter volume reduction in specific brain regions, such as the prefrontal cortex, was found in patients with bipolar disorder and those with unipolar depression. However, few studies have directly compared gray matter volumes between bipolar disorder and unipolar depression. In addition, it is unknown whether proinflammatory cytokines play a role in the gray matter volume difference between bipolar disorder and unipolar depression. METHODS: Twenty-three patients with bipolar disorder and 23 with unipolar depression in a mildly ill state (Clinical Global Impression-Severity ≤ 3) were enrolled in our study. Each participant underwent structural magnetic resonance imaging and proinflammatory cytokines examination. Voxel-based morphometry was performed to investigate the gray matter volume difference between bipolar disorder and unipolar depression. Correlations of the proinflammatory cytokines and the gray matter volume difference were analyzed. RESULTS: Several brain regions, including the orbitofrontal cortex, lingual gyrus, inferior frontal cortex, middle frontal cortex, and planum polare, were significantly smaller in patients with bipolar disorder than in those with unipolar depression. These gray matter volume differences between bipolar disorder and unipolar depression were negatively correlated with soluble IL-6 receptor levels. DISCUSSION: Proinflammatory cytokines, especially IL-6, were associated with the gray matter volumes in bipolar disorder and unipolar depression. However, the complicated associations between proinflammatory cytokines, neurocognitive function, and gray matter volumes require further investigation.