%0 Journal Article %J J Alzheimers Dis %D 2016 %T Comparison of Different Matrices as Potential Quality Control Samples for Neurochemical Dementia Diagnostics. %A Lelental, Natalia %A Brandner, Sebastian %A Kofanova, Olga %A Blennow, Kaj %A Zetterberg, Henrik %A Andreasson, Ulf %A Engelborghs, Sebastiaan %A Mroczko, Barbara %A Gabryelewicz, Tomasz %A Teunissen, Charlotte %A Mollenhauer, Brit %A Parnetti, Lucilla %A Chiasserini, Davide %A Molinuevo, José Luis %A Perret-Liaudet, Armand %A Verbeek, Marcel M %A Andreasen, Niels %A Brosseron, Frederic %A Bahl, Justyna M C %A Herukka, Sanna-Kaisa %A Hausner, Lucrezia %A Frölich, Lutz %A Labonte, Anne %A Poirier, Judes %A Miller, Anne-Marie %A Zilka, Norbert %A Kovacech, Branislav %A Urbani, Andrea %A Suardi, Silvia %A Oliveira, Catarina %A Baldeiras, Ines %A Dubois, Bruno %A Rot, Uros %A Lehmann, Sylvain %A Skinningsrud, Anders %A Betsou, Fay %A Wiltfang, Jens %A Gkatzima, Olymbia %A Winblad, Bengt %A Buchfelder, Michael %A Kornhuber, Johannes %A Lewczuk, Piotr %K Amyloid beta-Peptides %K Animals %K Anti-Bacterial Agents %K Biomarkers %K Cattle %K Clinical Chemistry Tests %K Dementia %K Humans %K Peptide Fragments %K Quality Control %K Reference Standards %K Serum Albumin, Bovine %K Sodium Azide %K tau Proteins %K Time Factors %K Tissue Preservation %X

BACKGROUND: Assay-vendor independent quality control (QC) samples for neurochemical dementia diagnostics (NDD) biomarkers are so far commercially unavailable. This requires that NDD laboratories prepare their own QC samples, for example by pooling leftover cerebrospinal fluid (CSF) samples.

OBJECTIVE: To prepare and test alternative matrices for QC samples that could facilitate intra- and inter-laboratory QC of the NDD biomarkers.

METHODS: Three matrices were validated in this study: (A) human pooled CSF, (B) Aβ peptides spiked into human prediluted plasma, and (C) Aβ peptides spiked into solution of bovine serum albumin in phosphate-buffered saline. All matrices were tested also after supplementation with an antibacterial agent (sodium azide). We analyzed short- and long-term stability of the biomarkers with ELISA and chemiluminescence (Fujirebio Europe, MSD, IBL International), and performed an inter-laboratory variability study.

RESULTS: NDD biomarkers turned out to be stable in almost all samples stored at the tested conditions for up to 14 days as well as in samples stored deep-frozen (at - 80°C) for up to one year. Sodium azide did not influence biomarker stability. Inter-center variability of the samples sent at room temperature (pooled CSF, freeze-dried CSF, and four artificial matrices) was comparable to the results obtained on deep-frozen samples in other large-scale projects.

CONCLUSION: Our results suggest that it is possible to replace self-made, CSF-based QC samples with large-scale volumes of QC materials prepared with artificial peptides and matrices. This would greatly facilitate intra- and inter-laboratory QC schedules for NDD measurements.

%B J Alzheimers Dis %V 52 %P 51-64 %8 2016 03 01 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26967210?dopt=Abstract %R 10.3233/JAD-150883 %0 Journal Article %J J Alzheimers Dis %D 2016 %T The Latent Dementia Phenotype δ is Associated with Cerebrospinal Fluid Biomarkers of Alzheimer's Disease and Predicts Conversion to Dementia in Subjects with Mild Cognitive Impairment. %A Koppara, Alexander %A Wolfsgruber, Steffen %A Kleineidam, Luca %A Schmidtke, Klaus %A Frölich, Lutz %A Kurz, Alexander %A Schulz, Stefanie %A Hampel, Harald %A Heuser, Isabella %A Peters, Oliver %A Reischies, Friedel M %A Jahn, Holger %A Luckhaus, Christian %A Hüll, Michael %A Gertz, Hermann-Josef %A Schröder, Johannes %A Pantel, Johannes %A Rienhoff, Otto %A Rüther, Eckart %A Henn, Fritz %A Wiltfang, Jens %A Maier, Wolfgang %A Jessen, Frank %A Kornhuber, Johannes %A Wagner, Michael %K Activities of Daily Living %K Aged %K Alzheimer Disease %K Amyloid beta-Peptides %K Biomarkers %K Cognitive Dysfunction %K Dementia %K Disease Progression %K Female %K Humans %K Logistic Models %K Longitudinal Studies %K Male %K Mental Status Schedule %K Middle Aged %K Neuropsychological Tests %K Peptide Fragments %K Phenotype %K Predictive Value of Tests %K Retrospective Studies %K tau Proteins %X

BACKGROUND: The recently proposed latent variable δ is a new tool for dementia case finding. It is built in a structural equation modeling framework of cognitive and functional data and constitutes a novel endophenotype for Alzheimer's disease (AD) research and clinical trials.

OBJECTIVE: To investigate the association of δ with AD biomarkers and to compare the prediction of δ with established scales for conversion to dementia in patients with mild cognitive impairment (MCI).

METHODS: Using data from a multicenter memory clinic study, we examined the external associations of the latent variable δ and compared δ with well-established cognitive and functional scales and cognitive-functional composite scores. For that purpose, logistic regressions with cerebrospinal fluid (CSF) biomarkers and conversion to dementia as dependent variables were performed with the investigated scores. The models were tested for significant differences.

RESULTS: In patients with MCI, δ based on a broad range of cognitive scales (including the ADAS-cog, the MMSE, and the CERAD neuropsychological battery) predicted an abnormal CSF Aβ42/tau ratio indicative of AD (n = 340, AUC = 0.78, p <  0.001), and predicted incident dementia within 1-3 years of follow-up (n = 525, AUC = 0.84, p <  0.001). These associations were generally stronger than for any other scale or cognitive-functional composite examined. Homologs of δ based on reduced test batteries yielded somewhat lower effects.

CONCLUSION: These findings support the interpretation of δ as a construct capturing the disease-related "essence" of cognitive and functional impairments in patients with MCI and dementia, and suggest that δ might become an analytical tool for dementia research.

%B J Alzheimers Dis %V 49 %P 547-60 %8 2016 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/26484902?dopt=Abstract %R 10.3233/JAD-150257 %0 Journal Article %J PLoS One %D 2010 %T Genetic evidence implicates the immune system and cholesterol metabolism in the aetiology of Alzheimer's disease. %A Jones, Lesley %A Holmans, Peter A %A Hamshere, Marian L %A Harold, Denise %A Moskvina, Valentina %A Ivanov, Dobril %A Pocklington, Andrew %A Abraham, Richard %A Hollingworth, Paul %A Sims, Rebecca %A Gerrish, Amy %A Pahwa, Jaspreet Singh %A Jones, Nicola %A Stretton, Alexandra %A Morgan, Angharad R %A Lovestone, Simon %A Powell, John %A Proitsi, Petroula %A Lupton, Michelle K %A Brayne, Carol %A Rubinsztein, David C %A Gill, Michael %A Lawlor, Brian %A Lynch, Aoibhinn %A Morgan, Kevin %A Brown, Kristelle S %A Passmore, Peter A %A Craig, David %A McGuinness, Bernadette %A Todd, Stephen %A Holmes, Clive %A Mann, David %A Smith, A David %A Love, Seth %A Kehoe, Patrick G %A Mead, Simon %A Fox, Nick %A Rossor, Martin %A Collinge, John %A Maier, Wolfgang %A Jessen, Frank %A Schürmann, Britta %A Heun, Reinhard %A Kölsch, Heike %A van den Bussche, Hendrik %A Heuser, Isabella %A Peters, Oliver %A Kornhuber, Johannes %A Wiltfang, Jens %A Dichgans, Martin %A Frölich, Lutz %A Hampel, Harald %A Hüll, Michael %A Rujescu, Dan %A Goate, Alison M %A Kauwe, John S K %A Cruchaga, Carlos %A Nowotny, Petra %A Morris, John C %A Mayo, Kevin %A Livingston, Gill %A Bass, Nicholas J %A Gurling, Hugh %A McQuillin, Andrew %A Gwilliam, Rhian %A Deloukas, Panos %A Al-Chalabi, Ammar %A Shaw, Christopher E %A Singleton, Andrew B %A Guerreiro, Rita %A Mühleisen, Thomas W %A Nöthen, Markus M %A Moebus, Susanne %A Jöckel, Karl-Heinz %A Klopp, Norman %A Wichmann, H-Erich %A Rüther, Eckhard %A Carrasquillo, Minerva M %A Pankratz, V Shane %A Younkin, Steven G %A Hardy, John %A O'Donovan, Michael C %A Owen, Michael J %A Williams, Julie %K Alzheimer Disease %K Apolipoproteins E %K Cholesterol %K Chromosome Mapping %K Genetic Predisposition to Disease %K Genome, Human %K Genome-Wide Association Study %K Humans %K Immune System %K Polymorphism, Single Nucleotide %X

BACKGROUND: Late Onset Alzheimer's disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes.

METHODOLOGY: We applied a recently developed tool for mining GWAS data for biologically meaningful information to a LOAD GWAS dataset. The principal findings were then tested in an independent GWAS dataset.

PRINCIPAL FINDINGS: We found a significant overrepresentation of association signals in pathways related to cholesterol metabolism and the immune response in both of the two largest genome-wide association studies for LOAD.

SIGNIFICANCE: Processes related to cholesterol metabolism and the innate immune response have previously been implicated by pathological and epidemiological studies of Alzheimer's disease, but it has been unclear whether those findings reflected primary aetiological events or consequences of the disease process. Our independent evidence from two large studies now demonstrates that these processes are aetiologically relevant, and suggests that they may be suitable targets for novel and existing therapeutic approaches.

%B PLoS One %V 5 %P e13950 %8 2010 %G eng %N 11 %1 http://www.ncbi.nlm.nih.gov/pubmed/21085570?dopt=Abstract %R 10.1371/journal.pone.0013950