title: A systematic review of amyloid-β peptides as putative mediators of the association between affective disorders and Alzheimer׳s disease.
abstract: BACKGROUND
  Affective disorders are associated with an increased occurrence of cognitive deficits and have been linked to cognitive impairment and Alzheimer׳s disease. The putative molecular mechanisms involved in these associations are however not clear. The aim of this systematic review was to explore clinically founded evidence for amyloid-β peptides in cerebrospinal fluid and blood as putative biomarkers for affective disorders.
  
  
  METHODS
  Systematic searches in Embase and PubMed databases yielded 23 eligible, observational studies.
  
  
  RESULTS
  Despite inconsistencies that were partly ascribed to the application of different assay formats, study results indicate a potentially altered amyloid-β metabolism in affective disorder.
  
  
  CONCLUSIONS
  Since most studies used a cross-sectional design, causality is difficult to establish. Moreover, methodological rigor of included studies varied and several studies were limited by very low sample numbers. Finally, different assays for amyloid-β were utilized in the different studies, thus hampering comparisons.
  
  
  CONCLUSIONS
  To unravel possible risk relations and causalities between affective disorder and Alzheimer׳s disease and to determine how amyloid-β concentrations change over time and are associated with cognition as well as affective symptomatology, future research should include prospective, longitudinal studies, implemented in large study populations, where peripheral and central amyloid-β ratios are quantified concomitantly and continuously across various affective phases. Also, to enable inter-survey comparisons, the use of standardized pre-analytical/analytical procedures is crucial.
authors: Department of Medicine, Kabbeltoft 25, DK-7100 Vejle, Denmark. Electronic address: leda.von.abbasowa@gmail.com.
authors: Leda
authors: L
authors: Abbasowa
authors: Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, University of Southern Denmark, Denmark; Department of Clinical Biochemistry, Immunology & Genetics, Statens Serum Institut, Copenhagen, Denmark.
authors: Niels H H
authors: NH
authors: Heegaard
mesh_terms: D000544:Alzheimer Disease / Q000150:complications / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D015415:Biomarkers; D003072:Cognition Disorders / Q000209:etiology; D006801:Humans; D019964:Mood Disorders / Q000150:complications / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers
keywords: Affective disorder; Alzheimer׳s disease; Amyloid-β; Biomarkers; CSF; Plasma