BACKGROUND: Oxidative stress is thought to mediate neuropathological processes of a number of neuropsychiatric disorders and recent data suggest that oxidative stress may be involved in the pathophysiology of bipolar disorder (BD). In the present investigation, we conducted a meta-analysis of studies that evaluated markers of oxidative stress in individuals with BD, as compared to healthy controls. METHODS: A Medline search was conducted to identify studies that measured peripheral markers of oxidative stress in bipolar disorder. Data were subjected to meta-analysis using a random effects model to examine the effect sizes of the pooled results. Bias assessment (Egger's test) and assessment of heterogeneity (I(2)) were also carried out. RESULTS: Thiobarbituric acidic reactive substances (TBARS) (p = 0.001) as well as NO activity (p = 0.02) were significantly increased in BD with a large effect size for TBARS and a moderate effect size for increase in NO. No significant effect sizes were observed for the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase (all p>0.05). LIMITATIONS: Some caution is warranted in interpreting these results: (1) Egger's test was positive for SOD, suggesting that SOD results may have been influenced by a publication bias. (2) We analyzed the absolute values of each antioxidant enzyme separately and the literature suggests that an imbalance between the antioxidant enzymes is a better indication of the presence of oxidative stress. CONCLUSIONS: The present meta-analysis suggests that oxidative stress markers are increased in BD and that oxidative stress may play a role in the pathophysiology of BD.
BACKGROUND: Oxidative stress is thought to mediate neuropathological processes of a number of neuropsychiatric disorders and recent data suggest that oxidative stress may be involved in the pathophysiology of bipolar disorder (BD). In the present investigation, we conducted a meta-analysis of studies that evaluated markers of oxidative stress in individuals with BD, as compared to healthy controls. METHODS: A Medline search was conducted to identify studies that measured peripheral markers of oxidative stress in bipolar disorder. Data were subjected to meta-analysis using a random effects model to examine the effect sizes of the pooled results. Bias assessment (Egger's test) and assessment of heterogeneity (I(2)) were also carried out. RESULTS:Thiobarbituric acidic reactive substances (TBARS) (p = 0.001) as well as NO activity (p = 0.02) were significantly increased in BD with a large effect size for TBARS and a moderate effect size for increase in NO. No significant effect sizes were observed for the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase (all p>0.05). LIMITATIONS: Some caution is warranted in interpreting these results: (1) Egger's test was positive for SOD, suggesting that SOD results may have been influenced by a publication bias. (2) We analyzed the absolute values of each antioxidant enzyme separately and the literature suggests that an imbalance between the antioxidant enzymes is a better indication of the presence of oxidative stress. CONCLUSIONS: The present meta-analysis suggests that oxidative stress markers are increased in BD and that oxidative stress may play a role in the pathophysiology of BD.
Authors: Rodrigo Machado-Vieira; Marcio G Soeiro-De-Souza; Erica M Richards; Antonio L Teixeira; Carlos A Zarate Journal: World J Biol Psychiatry Date: 2013-09-02 Impact factor: 4.132
Authors: Rafael T de Sousa; Carlos A Zarate; Marcus V Zanetti; Alana C Costa; Leda L Talib; Wagner F Gattaz; Rodrigo Machado-Vieira Journal: J Psychiatr Res Date: 2013-12-06 Impact factor: 4.791
Authors: Gustavo Scola; Helena K Kim; L Trevor Young; Mirian Salvador; Ana C Andreazza Journal: Psychopharmacology (Berl) Date: 2014-04-29 Impact factor: 4.530