Featured ArticleIncreased cerebrospinal fluid calpain activity and microparticle levels in Alzheimer's disease

BackgroundCalpain has been associated with the pathophysiology of Alzheimer's disease (AD) and with apoptotic neuronal cell death leading to microparticles (MPs) formation.MethodsA total of 64 patients with AD and 52 age- and gender-matched cognitively healthy elderly controls were included in the study. We measured calpain activity and levels of MPs, amyloid beta (Aβ1-42), h-tau, and p-tau181.ResultsAD patients showed significantly increased calpain activity and higher levels of MPs in cerebrospinal fluid (CSF) and significantly decreased calpain activity and lower levels of MPs in serum and plasma compared with healthy controls. Combined assessment of calpain activity and Aβ1-42 levels in CSF improved diagnostic accuracy as compared with singular or combined traditional CSF biomarkers of AD.ConclusionsThis is the first study showing increased calpain activity and microparticle levels in CSF of AD patients. Calpain activity could represent a novel diagnostic and prognostic biomarker and promising treatment target for AD.