title: Five out of 16 plasma signaling proteins are enhanced in plasma of patients with mild cognitive impairment and Alzheimer's disease.
abstract: Alzheimer's disease (AD) is a progressive neurodegenerative disorder with characteristic neuropathological changes of the brain. Great efforts have been undertaken to determine the progression of the disease and to monitor therapeutic interventions. Especially, the analysis of blood plasma had yielded incongruent results. Recently, Ray et al. (Nat. Med. 13, 2007, 1359f) identified changes of 18 signaling proteins leading to an accuracy of 90% in the diagnosis of AD. The aim of the present study was to examine 16 of these signaling proteins by quantitative Searchlight multiplex ELISA in order to determine their sensitivity and specificity in our plasma samples from AD, mild cognitive impairment (MCI), depression with and without cognitive impairment and healthy subjects. Quantitative analysis revealed an increased concentration in Biocoll isolated plasma of 5 out of these 16 proteins in MCI and AD patients compared to healthy subjects: EGF, GDNF and MIP1δ (in AD), MIP4 (in MCI) and RANTES (in MCI and AD). ROC analysis predicted a sensitivity of 65-75% and a specificity of 52-63% when comparing healthy controls versus MCI or AD. Depression without any significant cognitive deficits did not cause any significant changes. Depressed patients with significant cognitive impairment were not different from MCI patients. In conclusion, we detected a number of altered proteins that may be related to a disease specific pathophysiology. However, the overall expression pattern of plasma proteins could not be established as a biomarker to differentiate MCI from AD or from depression.
authors.affiliation: Department of General and Social Psychiatry, Innsbruck Medical University, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Marksteiner
authors.forename: Georg
authors.initials: G
authors.lastname: Kemmler
authors.forename: Elisabeth M
authors.initials: EM
authors.lastname: Weiss
authors.forename: Gabriele
authors.initials: G
authors.lastname: Knaus
authors.forename: Celine
authors.initials: C
authors.lastname: Ullrich
authors.forename: Sergei
authors.initials: S
authors.lastname: Mechtcheriakov
authors.forename: Harald
authors.initials: H
authors.lastname: Oberbauer
authors.forename: Simone
authors.initials: S
authors.lastname: Auffinger
authors.forename: Josef
authors.initials: J
authors.lastname: Hinterhölzl
authors.forename: Hartmann
authors.initials: H
authors.lastname: Hinterhuber
authors.forename: Christian
authors.initials: C
authors.lastname: Humpel
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000097:blood*; D000704:Analysis of Variance; D001798:Blood Proteins / Q000378:metabolism*; D003072:Cognition Disorders / Q000097:blood* / Q000150:complications; D003863:Depression / Q000097:blood / Q000150:complications; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008609:Mental Status Schedule; D009483:Neuropsychological Tests; D012372:ROC Curve
chemical_list: D001798:Blood Proteins