Associations between oxidative stress and perceived stress in patients with bipolar disorder and healthy control individuals

Abstract

Objective

Patients with neurodegenerative disorders, schizophrenia, and bipolar disorder present with increased oxidative stress markers. Not only is oxidative stress associated with development of disease, but also with increased disease progression and mortality. Oxidative stress reflects an increase in pro-oxidants, which subsequently leads to oxidative modifications of cellular components, such as RNA and DNA. Urinary excretion of 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) is the valid marker of whole-body RNA and DNA damage, respectively. Recently, cerebrospinal fluid (CSF) oxidative stress markers of RNA damage (8-oxoGuo) have showed both state and trait dependence in patients with bipolar disorder. However, the relation to subjective measures of stress and quality of life (QoL) is unknown.

Materials and methods

This prospective, longitudinal 1-year follow-up case-control study investigated the association between the oxidative stress markers, 8-oxoGuo and 8-oxodG and, perceived stress and QoL in patients with bipolar disorder (n = 86, 51% female) and gender-and-age-matched healthy control (HC) individuals (n = 44, 44% female). Oxidative stress markers obtained in CSF and urine were analysed using ultra-performance liquid chromatography–tandem mass spectrometry. The subjective perception of stress was assessed using the Perceived Stress Scale. Subjective evaluation of QoL was assessed using the World Health Organization Quality of Life questionnaire.

Results and conclusion

We found that markers of oxidative stress in CSF and urine were not associated with perceived stress and QoL quality in patients with bipolar disorder. However, a putative association between urinary 8-oxoGuo oxidative stress marker for RNA damage and perceived stress in HC encourages further investigations.

Keywords:

• Bipolar disorder
• oxidative stress
• perceived stress
• cerebrospinal fluid
• case-control

Acknowledgements

Ethical approval: The study was approved by the Local Ethical Committee (H-6-2014-006) and the Danish Data Protection Agency, Capital Region of Copenhagen. The study complied with the latest Declaration of Helsinki.

Disclosure statement

Authors UK, RAB, AHS, SGH, HEP, MA, and JF reported no biomedical financial interests or potential conflicts of interest. LVK reported having been a consultant for Lundbeck within the preceding three years. 

Data availability statement

The data that support the findings of this study are available from the corresponding author (UK) upon reasonable request.

Additional information

Funding

The study was supported by The Mental Health Services of Capital of Denmark Research Foundation, AP Møller Foundation for Promotion of Medical Science, The Beckett Foundation, The King Christian 10th Foundation and the Max and Oda Wørzner Foundation (recipient author UK). The Danish Dementia Research Centre is supported by grants from the Danish Ministry of Health (J No. 2007-12143-112, project 59506/J No. 0901110, project 34501) and the Danish Health Foundation (J No. 2007B004).

Notes on contributors

Ulla Knorr

Contributors UK, RAS, HEP, JF, MA and LVK conceived the study and authored the protocol. All authors helped implement the study. All authors contributed to, and approved the final version of the manuscript.