Proteomic approaches to identify blood-based biomarkers for depression and bipolar disorders

ABSTRACT

Introduction: Major depressive disorder (MDD) and bipolar disorder (BD) are leading causes of disability worldwide, yet many people remain undiagnosed, are misdiagnosed, and/or ineffectively treated. Diagnosis relies on the clinical assessment of symptoms, and there is currently no molecular or brain-imaging diagnostic test available. Identifying and validating protein biomarkers could provide a more accurate and objective means of diagnosis.

Areas covered: Proteomics is a powerful tool that enables the identification and quantification of novel candidate biomarkers of disease. In this review, we discuss the role of proteomic technologies in biomarker discovery and validation, peripheral blood as a source of protein biomarkers, statistical methods for analyzing proteomic data, and some existing challenges in the field. We also review a selection of previously published studies focused on identifying blood-based diagnostic protein biomarkers of MDD and BD within a ten-year period.

Expert commentary: Proteomic studies have led to the identification of numerous potential biomarkers of MDD and BD. However, clinical validation and translation into clinical practice have not yet been achieved. Conducting large-scale validation studies and addressing various factors that limit the reproducibility of the proteomic findings are key to ensure that robust and reliable biomarker tests are developed and clinically validated.

KEYWORDS:

• Major depressive disorder
• bipolar disorder
• affective disorders
• proteomic
• blood
• dried blood spots
• mass spectrometry
• diagnostic
• biomarkers
• statistical methods

Acknowledgments

This study was supported by the Stanley Medical Research Institute (SMRI). We also thank Dr Jason Cooper, Dr Sureyya Ozcan, Dr Jakub Tomasik and Anthony Olmert for their valuable insights and constructive comments.

Declaration of interest

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Supplemental data

Supplemental data for this article can be accessed here.

Additional information

Funding

This article was supported by a grant from the Stanley Medical Research Institute: 07R-1888.