Decreased expression of heme oxygenase is associated with depressive symptoms and may contribute to depressive and hypertensive comorbidity

Abstract

Background: There is strong evidence that hypertension and depression are comorbid and oxidative stress is implicated in both pathologies. We aimed to elucidate the relationship between biochemical markers of the antioxidant-pro-oxidant equilibrium and depression in hypertension.

Methods: Blood was collected from patients diagnosed with depression, hypertension, or comorbid depression and hypertension and healthy age- and sex-matched controls. Whole blood reduced glutathione, erythrocyte superoxide dismutase (SOD-1), glutathione peroxidase (GPx-1), glutathione reductase (GR), malondialdehyde (MDA), and plasma hydrogen peroxide (H₂O₂) were assayed using spectrophotometry, and heme oxygenase (HO-1) levels were determined immunoenzymatically.

Results: Both hypertension and depression were associated with altered antioxidant-pro-oxidant profiles. Decreased GPx-1 and SOD-1 activities, increased GR activity, increased levels of GSH, and increased concentrations of MDA and H₂O₂ were observed in patients compared to controls. Inducible HO-1 was specifically decreased in patients with depression and was significantly associated with both the prevalence and severity of depressive symptoms.

Conclusions: Heme oxygenase is a biological factor that might explain the relationship between inflammation, oxidative stress, and the biological and functional changes in brain activity in depression. HO-1 is a candidate depression biomarker and provides an avenue for novel preventative and diagnostic strategies against this disease.

Keywords:

• Depression
• Hypertension
• Oxidative stress
• Heme oxygenase
• Antioxidant enzymes

Acknowledgement

This study was funded by the research grant awarded to Joanna Rybka from the Ministry of Science and Higher Education.

Disclaimer statements

Contributors None.

Funding None.

Conflicts of interest There are no conflicts-of-interest.

Ethics approval Written informed consent was obtained from all the participants of the study. The study was approved by the Nicolaus Copernicus University in Torun Human Ethics Committee and was conducted under the tenets of the Declaration of Helsinki.