TY - JOUR

T1 - Cerebrospinal fluid synaptic biomarker changes in bipolar disorder – A longitudinal case-control study

AU - Knorr, Ulla

AU - Simonsen, Anja Hviid

AU - Nilsson, Johanna

AU - Brinkmalm, Ann

AU - Zetterberg, Henrik

AU - Blennow, Kaj

AU - Knudsen, Mark Bech

AU - Forman, Julie

AU - Hasselbalch, Steen Gregers

AU - Kessing, Lars Vedel

N1 - Publisher Copyright: © 2024 The Authors

PY - 2024

Y1 - 2024

N2 - Background: This exploratory study investigated cerebrospinal fluid (CSF) synaptic protein biomarkers in bipolar disorder (BD), aiming to highlight the neurobiological basis of the disorder. With shared cognitive impairment features between BD and Alzheimer's disease, and considering increased dementia risk in BD patients, the study explores potential connections. Methods: Fifty-nine well-characterized patients with BD and thirty-seven healthy control individuals were examined and followed for one year. Synaptic proteins encompassing neuronal pentraxins (NPTX)1, NPTX2, and NPTX-receptor, 14–3-3 protein family epsilon, and zeta/delta, activating protein-2 complex subunit beta, synucleins beta-synuclein and gamma-synuclein, complexin-2, phosphatidylethanolamine-binding protein 1, rab GDP dissociation inhibitor alpha, and syntaxins 1B and 7 were measured in CSF using a microflow liquid chromatography-mass spectrometric multiple reaction monitoring set-up. Biomarker levels were compared between BD and HC and in BD before, during, and after mood episodes. Results: The synaptic proteins revealed no statistically significant differences between BD and HC, neither at baseline, one-year follow-up, or in terms of changes from baseline to follow-up. Moreover, the CSF synaptic protein levels in patients with BD were unaltered compared to baseline when they stabilized in euthymia following an affective episode and at one-year follow-up. Limitation: It is uncertain what the CSF biomarker concentrations reflect since we yet do not know the mechanisms of release of these proteins, and we are uncertain of what increased or decreased levels reflect. Conclusion: This first-ever investigation of a panel of CSF protein biomarkers of synaptic dysfunction in patients with BD and HC individuals found no statistically significant differences cross-sectionally or longitudinally.

AB - Background: This exploratory study investigated cerebrospinal fluid (CSF) synaptic protein biomarkers in bipolar disorder (BD), aiming to highlight the neurobiological basis of the disorder. With shared cognitive impairment features between BD and Alzheimer's disease, and considering increased dementia risk in BD patients, the study explores potential connections. Methods: Fifty-nine well-characterized patients with BD and thirty-seven healthy control individuals were examined and followed for one year. Synaptic proteins encompassing neuronal pentraxins (NPTX)1, NPTX2, and NPTX-receptor, 14–3-3 protein family epsilon, and zeta/delta, activating protein-2 complex subunit beta, synucleins beta-synuclein and gamma-synuclein, complexin-2, phosphatidylethanolamine-binding protein 1, rab GDP dissociation inhibitor alpha, and syntaxins 1B and 7 were measured in CSF using a microflow liquid chromatography-mass spectrometric multiple reaction monitoring set-up. Biomarker levels were compared between BD and HC and in BD before, during, and after mood episodes. Results: The synaptic proteins revealed no statistically significant differences between BD and HC, neither at baseline, one-year follow-up, or in terms of changes from baseline to follow-up. Moreover, the CSF synaptic protein levels in patients with BD were unaltered compared to baseline when they stabilized in euthymia following an affective episode and at one-year follow-up. Limitation: It is uncertain what the CSF biomarker concentrations reflect since we yet do not know the mechanisms of release of these proteins, and we are uncertain of what increased or decreased levels reflect. Conclusion: This first-ever investigation of a panel of CSF protein biomarkers of synaptic dysfunction in patients with BD and HC individuals found no statistically significant differences cross-sectionally or longitudinally.

KW - Biomarkers

KW - Bipolar disorder

KW - Case-control

KW - Cerebrospinal fluid

KW - Longitudinal

KW - Synaptic dysfunction

U2 - 10.1016/j.jad.2024.05.034

DO - 10.1016/j.jad.2024.05.034

M3 - Journal article

C2 - 38723679

AN - SCOPUS:85192453215

VL - 358

SP - 250

EP - 259

JO - Journal of Affective Disorders

JF - Journal of Affective Disorders

SN - 0165-0327

ER -