Researchers from Nagoya City University (Japan) have published a study reporting flotillin as a novel diagnostic blood marker of Alzheimer’s disease (AD). The study indicates that serum flotillin levels are negatively associated with brain amyloid deposition and – through acting as a biomarker to estimate brain amyloid deposition – could improve the early diagnosis of AD.
Current markers and techniques employed in the diagnosis of AD include decreased levels of amyloid-β protein 42, increased levels of phosphorylated tau in cerebrospinal fluid (CSF) and positron emission tomography imaging, in which Pittsburgh compound B is used to visualize amyloid deposition in the brain. The costs and invasiveness of these current diagnostic techniques remain challenges in AD diagnosis.
Previous research has demonstrated that the release of flotillin – an exosome marker – is decreased by the presence of amyloid-β protein. In this study, published in the Journal of Alzheimer’s Disease, lead investigator Makoto Michikawa (Nagoya City University) and his collaborators aimed to determine whether flotillin levels are reduced in the CSF and/or serum of individuals with AD, and provide a less invasive, less expensive and easily detectable blood biomarker for the early diagnosis of AD.
In the study, the team used western blotting techniques to analyze the flotillin levels in the CSF and serum of non-AD controls, individuals with AD and patients with mild cognitive impairment (MCI). The cerebroventricular fluid and serum of AD, vascular dementia and non-AD autopsy cases were also analyzed by western blotting.
Researchers observed that flotillin levels were significantly decreased in the CSF and serum of individuals with AD compared with non-AD controls. Moreover, in patients with MCI due to AD, determined by traditional positron emission tomography techniques, CSF and serum flotillin levels were significantly decreased compared with those of patients with MCI not resulting from AD. No changes in flotillin levels in cerebroventricular fluid and serum samples of individuals with vascular dementia were observed.
The study concludes that serum flotillin levels appear to be negatively associated with brain amyloid deposition, as indicated by Pitssburgh compound B uptake. The team suggest that serum flotillin levels could serve as a blood marker to estimate brain amyloid deposition and potentially improve the early diagnosis of AD.
Source: Abdullah M, Kimura N, Akatsu H et al. Flotillin is a novel diagnostic blood marker of Alzheimer’s disease. J. Alzheimer’s Dis. doi:10.3233/JAD-190908 (2019) (Epub ahead of print)