%0 Journal Article %J J Alzheimers Dis %D 2016 %T Association between Cerebrospinal Fluid Biomarkers for Alzheimer's Disease, APOE Genotypes and Auditory Verbal Learning Task in Subjective Cognitive Decline, Mild Cognitive Impairment, and Alzheimer's Disease. %A Mandecka, Monika %A Budziszewska, Magdalena %A Barczak, Anna %A Pepłońska, Beata %A Chodakowska-Żebrowska, Małgorzata %A Filipek-Gliszczyńska, Anna %A Nesteruk, Marta %A Styczyńska, Maria %A Barcikowska, Maria %A Gabryelewicz, Tomasz %X

In the course of Alzheimer's disease (AD), early pathological changes in the brain start decades before any clinical manifestation. The concentration levels of AD cerebrospinal fluid (CSF) biomarkers, such as amyloid-β1-42 (Aβ1-42), total tau (T-tau), and phosphorylated tau (P-tau), may reflect a cerebral pathology facilitating an early diagnosis of the disease and predicting a cognitive deterioration. The aim of this study was to estimate the prevalence of AD CSF biomarkers in those individuals with a subjective cognitive decline (SCD), a mild cognitive impairment (MCI), and Alzheimer's dementia (AD-D), together with the relationships between the biomarkers, an APOE ɛ4 presence, and a verbal episodic memory performance. We included 252 patients from the memory clinic with a diagnosis of SCD (n = 85), MCI (n = 87), and AD-D (n = 80). A verbal episodic memory performance level was assessed and was based on a delayed recall trial from the 10-word list of an auditory verbal learning task (AVLT). We found that the patients with more severe cognitive impairments had significantly lower levels of Aβ1-42 and higher levels of T-tau and P-tau. This pattern was also typical for the APOE ɛ4 carriers, who had lower levels of Aβ1-42 than the noncarriers in the AD-D and MCI groups. The levels of T-tau and P-tau were significantly higher in the APOE ɛ4 carriers than in the noncarriers, but only in the MCI patients. The AVLT performance in the whole study samples was predicted by age, Aβ1-42, and the T-tau CSF biomarkers, but not by the APOE genotyping.

%B J Alzheimers Dis %V 54 %P 157-68 %8 2016 Jul 29 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/27472875?dopt=Abstract %R 10.3233/JAD-160176 %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