Biomarkers for neurodegeneration impact cognitive function: a longitudinal 1-year case–control study of patients with bipolar disorder and healthy control individuals

Ulla Knorr*, Anja Hviid Simonsen, Henrik Zetterberg, Kaj Blennow, Mira Willkan, Julie Forman, Kamilla Miskowiak, Steen Gregers Hasselbalch, Lars Vedel Kessing

*Corresponding author af dette arbejde

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

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Abstract

Background
Abnormalities in cerebrospinal fluid (CSF)-amyloid-beta (Aβ)42, CSF-Aβ40, CSF-Aβ38, CSF-soluble amyloid precursor proteins α and β, CSF-total-tau, CSF-phosphorylated-tau, CSF-neurofilament light protein (NF-L), CSF-neurogranin, plasma-Aβ42, plasma-Aβ40, plasma-total-tau, plasma-NF-L and, serum-S100B during affective episodes may reflect brain changes that could impact cognitive function in patients with bipolar disorder (BD). The study aimed to investigate the association between these biomarkers indicative of Alzheimer’s disease and those reflecting neurodegeneration alongside their impact on cognitive function in patients with BD and healthy control individuals (HC). The primary hypothesis was that GL and VL would increase with increasing levels of CSF-Aβ42 based on data from T0 and T3 in BD and HC jointly.

Methods
In a prospective, longitudinal case–control study euthymic patients with BD (N = 85) and HC (N = 44) were evaluated with clinical assessment and neuropsychological testing at baseline (T0) and during euthymia after a year (T3). Patients’ affective states were recorded weekly as euthymic, subthreshold level, major depression, or (hypo)mania. If an episode occurred during follow-up, the patient was also assessed in post-episode euthymia. Cognitive performance was measured as a global cognitive score (GL) for four cognitive domains including verbal learning and memory (VL).

Results
Estimated in a linear mixed model GL increased with 0.001 for each increase of 1 pg/ml of CSF-Aβ42 (97.5%, CI 0.00043–0.0018, adjusted-p = 0.0005) while VL increased by 0.00089 (97.5%, CI 0.00015–0.0018, adjusted-p = 0.045) in BD and HC jointly. The association was weak, however stronger in patients with BD compared to HC. Associations between other biomarkers including CSF-neurogranin, and cognitive domains were overall weak, and none remained significant after adjustment for multiple testing.

Limitations
Modest sample size. A complete data set regarding both CSF-AB-42 and cognitive test scores was obtained from merely 61 patients with BD and 38 HC individuals.

Conclusion
CSF-Aβ42 may be associated with cognitive dysfunction in patients with BD and HC individuals. The association appeared to be stronger in BD but with overlapping confidence intervals. Hence it remains uncertain whether the association is a general phenomenon or driven by BD.
OriginalsprogEngelsk
Artikelnummer2
TidsskriftInternational Journal of Bipolar Disorders
Vol/bind12
Udgave nummer1
Antal sider12
ISSN2194-7511
DOI
StatusUdgivet - 2024

Bibliografisk note

Funding Information:
Open access funding provided by Copenhagen University. UK is appointed as an associated professor at the University of Copenhagen and Mental Health Services—Capital Region of Denmark. AHS is funded by Absalonfonden. KWM has received consultancy fees from Lundbeck and Janssen-Cilag in the past 3 years. KWM, SGH, and LVK are appointed as professors at the University of Copenhagen and Mental Health Services—Capital Region of Denmark. HZ is a Wallenberg Scholar supported by grants from the Swedish Research Council (#2018-02532), the European Research Council (#681712), Swedish State Support for Clinical Research (#ALFGBG-720931), the Alzheimer Drug Discovery Foundation (ADDF), USA (#201809-2016862), the AD Strategic Fund and the Alzheimer's Association (#ADSF-21-831376-C, #ADSF-21-831381-C and #ADSF-21-831377-C), the Olav Thon Foundation, the Erling-Persson Family Foundation, Stiftelsen för Gamla Tjänarinnor, Hjärnfonden, Sweden (#FO2019-0228), the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 860197 (MIRIADE), and the UK Dementia Research Institute at UCL. KB holds the Torsten Söderberg Professorship in medicine and receives funding from the Swedish Research Council and the ALFGBG.

Funding Information:
We thank the participants for their contribution to the study. 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 U.K.). 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).

Publisher Copyright:
© 2024, The Author(s).

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