Leda Abbasowa1, Niels H H Heegaard2. 1. Department of Medicine, Kabbeltoft 25, DK-7100 Vejle, Denmark. Electronic address: leda.von.abbasowa@gmail.com. 2. 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.
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. METHOD: 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. LIMITATIONS: 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. CONCLUSION: 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.
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. METHOD: 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. LIMITATIONS: 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. CONCLUSION: 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: Nunzio Pomara; Davide Bruno; Ricardo S Osorio; Chelsea Reichert; Jay Nierenberg; Antero S Sarreal; Raymundo T Hernando; Charles R Marmar; Thomas Wisniewski; Henrik Zetterberg; Kaj Blennow Journal: Neuroreport Date: 2016-09-28 Impact factor: 1.837