The study evaluated whether the activity of the indoleamine 2,3 dioxygenase (IDO) enzyme is increased post-stroke and contributes to the development of post-stroke depression (PSD) via tryptophan (TRP) depletion and neurotoxic kynurenine (KYN) metabolite production. The activity of IDO was measured using the KYN/TRP ratio. Participants were assessed for depression severity using the Center for Epidemiological Studies Depression Scale (CES-D). Blood TRP, KYN, large neutral amino acids and cytokines were measured and compared. Fifty-four (mean age=69.9±15.2, male=52.7%, mean NIHSS=7.3±4.6) patients within 28.9±40.3 days of stroke were separated into two groups: non-depressed (n=38, CES-D=6.1±4.9) and those with significant depressive symptoms (n=16, CES-D=26.8±10.8). Higher mean KYN/TRP ratios were demonstrated in stroke patients with depressive symptoms (non-depressed=69.3±36.9 vs. depressive symptoms=78.3±42.0, F3,50=4.61, p=0.006) after controlling for LNAA (p=0.026) and hypertension (p=0.039). As the KYN/TRP ratio reflects decreased TRP and increased neurotoxic KYN metabolites, both mechanisms may play an etiological role in PSD.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/25520 |
| Date | 30 December 2010 |
| Creators | Wong, Amy |
| Contributors | Lanctôt, Krista, Herrmann, Nathan |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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