Association of Platelet Serotonin Levels in Alzheimer’s Disease with Clinical and Cerebrospinal Fluid Markers

Article type: Research Article

Authors: Tajeddinn, Walid^{a; *} | Fereshtehnejad, Seyed-Mohammad^a | Seed Ahmed, Mohammed^{a; b; c} | Yoshitake, Takashi^d | Kehr, Jan^d | Shahnaz, Tasmin^{a; h} | Milovanovic, Micha^{a; h} | Behbahani, Homira^a | Höglund, Kina^{a; g} | Winblad, Bengt^a | Cedazo-Minguez, Angel^a | Jelic, Vesna^a | Järemo, Petter^{a; h} | Aarsland, Dag^{a; e; f}

Affiliations: [a] Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division for Neurogeriatrics, Karolinska Institutet, Novum, Huddinge, Stockholm, Sweden | [b] King’s College London, Wolfson Centre for Age Related-Diseases, London, UK | [c] Department of Physiology, Faculty of Medicine, University of Khartoum, Khartoum, Sudan | [d] Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden | [e] Centre for Age-Related Medicine, Stavanger University Hospital, Stavanger, Norway | [f] Department of Neurology, Akershus University Hospital, Oslo, Norway | [g] Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden | [h] Department of Internal Medicine, the Vrinnevi Hospital, Norrköping, Sweden

Correspondence: [*] Correspondence to: Walid Tajeddinn, MD, MSc, Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division for Neurogeriatrics, Karolinska Institutet, Novum, Blickagången 6, 141 57 Huddinge, Sweden. Tel.: +249 46883894; Fax: +249 08 585 85470; E-mail: walidtag501@gmail.com.

Abstract: Introduction: Serotonin (5-HT) is involved in the pathology of Alzheimer’s disease (AD). Objective: We aimed to measure 5-HT level in platelets in AD and explore its association with cerebrospinal fluid (CSF), AD biomarkers (amyloid-β 1-42 (Aβ42), total tau (t-tau), and phosphorylated tau (p-tau)), and clinical symptoms. Methods: 15 patients with AD and 20 patients with subjective cognitive impairment (SCI) were included. 5-HT metabolites were measured, in a specific fraction, using high performance liquid chromatography with electrochemical detection (HPLC-ECD). Results: Significantly lower 5-HT concentrations were observed in AD patients compared to SCI patients both after normalization against total protein (p = 0.008) or platelet count (p = 0.019). SCI patients with lower 5-HT level have higher AD CSF biomarkers, total tau (p = 0.026) and tau/Aβ42 ratio (p = 0.001), compared to those with high 5-HT levels. Conclusion: AD patients have reduced platelet 5-HT levels. In SCI, lower 5-HT content was associated with a higher AD-CSF biomarker burden.

Keywords: Alzheimer’s disease, amyloid, cognition, platelet, serotonin

DOI: 10.3233/JAD-160022

Journal: Journal of Alzheimer's Disease, vol. 53, no. 2, pp. 621-630, 2016