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Beech RD, Lowthert L, Leffert JJ, Mason PN, Taylor MM, Umlauf S, Lin A, Lee JY, Maloney K, Muralidharan A, Lorberg B, Zhao H, Newton SS, Mane S, Epperson CN, Sinha R, Blumberg H, Bhagwagar Z. Increased peripheral blood expression of electron transport chain genes in bipolar depression. Bipolar Disord 2010; 12:813-24. [PMID: 21176028 PMCID: PMC3076072 DOI: 10.1111/j.1399-5618.2010.00882.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To identify specific genetic pathways showing altered expression in peripheral blood of depressed subjects with bipolar disorder (BPD). METHODS Illumina Sentrix BeadChip (Human-6v2) microarrays containing >48,000 transcript probes were used to measure levels of gene expression in peripheral blood from 20 depressed subjects with BPD and in 15 healthy control subjects. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to confirm a subset of these differences. RESULTS A total of 1,180 genes were differentially expressed between subjects with BPD and healthy controls (fold-change >1.3, false discovery rate-corrected p < 0.05, covaried for age and sex). Of these, 559 genes were up-regulated in BPD subjects and 621 were down-regulated. Surprisingly, there was no difference between medicated (n = 11) and unmedicated (n = 9) subjects with BPD for any of these genes. Pathway analysis using GeneGo MetaCore software showed that the most significantly affected pathway was the mitochondrial electron transport chain (ETC). Of the 85 objects (genes or proteins) in this pathway, 22 were up-regulated and 2 down-regulated in subjects with BPD. qRT-PCR confirmed up-regulation of nuclear encoded ETC genes in complexes I, III, IV, and V and, in addition, demonstrated up-regulation of mitochondrially encoded genes in each of these complexes. CONCLUSION These results suggest that increased expression of multiple components of the mitochondrial ETC may be a primary deficit in bipolar depression, rather than an effect of medication.
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Affiliation(s)
- Robert D Beech
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, USA.
| | - Lori Lowthert
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Janine J Leffert
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Portia N Mason
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Mary M Taylor
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Sheila Umlauf
- W. M. Keck Foundation Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven
| | - Aiping Lin
- W. M. Keck Foundation Biostatistics Resource, Yale University School of Medicine, New Haven
| | - Ji Young Lee
- W. M. Keck Foundation Biostatistics Resource, Yale University School of Medicine, New Haven
| | - Kathleen Maloney
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | | | - Boris Lorberg
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Hongyu Zhao
- Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven
| | - Samuel S Newton
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Shrikant Mane
- W. M. Keck Foundation Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven
| | - C Neill Epperson
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Rajita Sinha
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Hilary Blumberg
- Department of Psychiatry, Yale University School of Medicine, New Haven
| | - Zubin Bhagwagar
- Department of Psychiatry, Yale University School of Medicine, New Haven, Neuroscience Global Clinical Research, Bristol-Myers Squibb, Wallingford, CT, USA
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Abstract
OBJECTIVE To describe a patient with longstanding depression and hypothyroidism who had marked mood improvement only after triiodothyronine (T3) was added to her thyroxine (T4) replacement therapy. CASE SUMMARY A 50-year-old white woman had a long history of depression and documented hypothyroidism since 1991. Despite treatment with T4 with dosages up to 0.3 mg/d, she continued to be depressed, have symptoms of hypothyroidism, and have a persistently elevated thyroid-stimulating hormone concentration. Addition of a low dose of T3 to her regimen resulted in significant mood improvement. DISCUSSION The relationship between hypothyroidism and depression is well known. It is possible that this patient's long history of depression may have been a consequence of inadequately treated hypothyroidism, due either to poor patient compliance or resistance to T4. Nevertheless, her depression responded to addition of a low dose of T3 to her regimen. This case emphasizes the importance of screening depressed patients for hypothyroidism. Her clinical course also suggests that depression related to hypothyroidism may be more responsive to a regimen that includes T3 rather than to replacement with T4 alone. This is consistent with the observation that T3 is superior to T4 as adjuvant therapy in the treatment of unipolar depression. CONCLUSIONS Depressed patients should be screened for hypothyroidism. In hypothyroid patients, depression may be more responsive to a replacement regimen that includes T3 rather than T4 alone. Therefore, inclusion of T3 in the treatment regimen may be warranted after adequate trial with T4 alone.
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Affiliation(s)
- S K Rack
- Department of Behavioral Medicine and Psychiatry, School of Medicine, West Virginia University, Morgantown 26505, USA.
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