Platelet a disintegrin and metallopeptidase 10 expression correlates with clock drawing test scores in Alzheimer’s disease Patrícia Regina Manzine 1 , Elizabeth Joan Barham 2 , Francisco Assis Carvalho Vale 3 , Heloisa Sobreiro Selistre-de-Araújo 4 , Sofia Cristina Iost Pavarini 1 and Márcia Regina Cominetti 1 1 Departamento de Gerontologia, UFSCar, São Carlos, São Paulo, Brazil 2 Departamento de Psicologia, UFSCar, São Carlos, São Paulo, Brazil 3 Departamento de Medicina, UFSCar, São Carlos, São Paulo, Brazil 4 Departamento de Ciências Fisiológicas, UFSCar, São Carlos, São Paulo, Brazil Correspondence to: M. R. Cominetti, PhD, E-mail: mcominetti@ufscar.br Objective: Earlier studies have demonstrated that a disintegrin and metallopeptidase 10 (ADAM10) levels are reduced in Alzheimer’s disease (AD) patients compared with healthy subjects. The objective of this study was to evaluate whether platelet ADAM10 levels correlates with the clock drawing test (CDT) scores, which is a simple and a reliable measure of visuospatial ability and executive function in AD patients. Methods: Thirty elderly patients with probable AD and 25 healthy patients forming the control group, matched by age, gender, and educational level, were evaluated. Platelet proteins were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, and ADAM10 was identified by western blotting. The Spearman’s correlation coefficient between ADAM10 and CDT was obtained for each group. The areas under the curves were used to compare the receiver operating characteristic curves. Results: The CDT scores and platelet ADAM10 expression were significantly different between patients with AD and controls and also along the disease’s progression. In AD patients, there was a positive correlation between ADAM10 expression and CDT scores. Among non-AD subjects, no correlation was found. The combination of ADAM10 and CDT was significantly better to confirm the AD diagnosis than the AUCs of ADAM10 and CDT separately. Conclusions: The association of blood-based biomarkers, such as ADAM10, and cognitive tests may be helpful for a more reliable AD diagnosis. Copyright # 2013 John Wiley & Sons, Ltd. Key words: Alzheimer’s disease; ADAM10; clock drawing test; biomarkers; platelet; elderly patients History: Received 29 May 2013; Accepted 30 July 2013; Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/gps.4020 Introduction Despite considerable efforts, there are no approved disease-modifying treatments for Alzheimer’s disease (AD). In addition, pathology precedes clinical symp- toms by years (Henriksen et al., 2013). As a conse- quence of this scenario, in recent years, research on AD has focused on finding of reliable diagnostic biomarkers that enable earlier and accurate disease de- tection (Fletcher et al., 2013). Established biomarkers showing acceptable sensitiv- ity and specificity for AD diagnosis include total-Tau (tTau), phosphorylated-Tau (pTau 181 ), and amyloid-β (Aβ) molecules found in the cerebrospinal fluid (CSF) (Blennow et al., 2010), as well as structural or functional imaging studies (Frisoni et al., 2010). Furthermore, some interesting biomarkers have been described to directly bind Aβ as visualized by positron emission tomography imaging (Okamura and Yanai, 2010). However, these invasive and high cost methods are Copyright # 2013 John Wiley & Sons, Ltd. Int J Geriatr Psychiatry (2013) RESEARCH ARTICLE