Research Article

Peripheral oxidative damage in early-stage mood disorders: a nested population-based case-control study

Pedro V. S. Magalhães^a1, Karen Jansen^a2, Ricardo Tavares Pinheiro^a2, Gabriela Delevati Colpo^a1a3, Leonardo Lisbôa da Motta^a3, Fábio Klamt^a3, Ricardo Azevedo da Silva^a2 and Flávio Kapczinski^a1 c1

^a1 National Institute for Translational Medicine, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil

^a2 Programa de Pós-Graduação em Saúde e Comportamento, Universidade Católica de Pelotas, Brazil

^a3 Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Brazil

Abstract

Systemic toxicity is a relevant dimension of pathophysiology in bipolar disorder, and oxidative damage is one potential link between central and peripheral pathology. Although there is mounting evidence that chronic bipolar disorder is associated with oxidative stress, studies in the early stages of bipolar disorder are scarce, and heavily reliant on clinical in lieu of population studies. The objective of this study was to confirm leading hypotheses about the role of oxidative damage in bipolar disorder. To that end, we nested a case-control study in a population-based study of young adults aged 18–24 yr. After an initial psychopathology screen, all people with a lifetime history of (hypo)mania and matched controls underwent a structured diagnostic interview. This yielded a sample of 231 participants, in whom we measured serum protein carbonyl content (PCC) and thiobarbituric acid reactive substances (TBARS). People with bipolar disorder had higher PCC levels than healthy subjects. Those with major depression were not different from control subjects in either PCC or TBARS levels. Both bipolar disorder and major depression were associated with higher PCC levels in the a priori regression model controlling for possible confounders. These findings indicate that protein oxidative damage is present from early stages and can be seen as a sign of early illness activity in mood disorders.

(Received April 21 2011)

(Reviewed June 08 2011)

(Revised August 11 2011)

(Accepted September 02 2011)

Key Words:

• Bipolar disorder;
• major depression;
• oxidative stress;
• population-based study;
• protein carbonyl content;
• thiobarbituric acid reactive substances

Correspondence:

^c1 Address for correspondence: Professor F. Kapczinski, Laboratório de Psiquiatria Molecular, Hospital de Clinicas de Porto Alegre (HCPA), Ramiro Barcelos, 2350, CEP 90035-003, Porto Alegre, RS, Brazil. Tel.: +55 51 21018845 Fax: +55 51 21018846 Email: kapcz@terra.com.br