Affiliations: [a]
Institute of Physiology and Coimbra Institute for Clinical and Biomedical Researh (iCBR), Faculty of Medicine, University of Coimbra, Portugal
| [b]
Department of Neurology, Centro Hospitalar e Universitário de Coimbra, Portugal
| [c] Faculty of Medicine, University of Coimbra, Portugal
| [d]
Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Portugal
| [e]
Institute of Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Portugal
Correspondence:
[*]
Correspondence to: Liliana Letra, Institute of Physiology and Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal. Tel.: +00351 91935895; E-mail: lrletra@fmed.uc.pt.
Abstract: Background:Adipose tissue dysfunction has been implicated in the pathophysiology of Alzheimer’s disease. However, the involvement of adipokines, particularly adiponectin, remains unclear. Objective:To compare serum and cerebrospinal fluid (CSF) levels of adiponectin, leptin and leptin-to-adiponectin ratio in patients within the spectrum of Alzheimer’s disease and evaluate their relationship with classical biomarkers and their value as markers of progression. Methods:Amnestic mild cognitive impairment (MCI, n = 71) and Alzheimer’s dementia (AD, n = 53) subjects were consecutively recruited for serum and CSF adiponectin and leptin determination using an analytically validated commercial enzyme-linked immunosorbent assay (ELISA). Correlations were explored using adjusted Spearman’s correlation coefficients. A logistic regression model and ROC analysis were performed to evaluate the staging predictive value of adipokines. Results:Serum adiponectin was 33% higher in AD when compared to MCI patients. Adiponectin CSF levels, similar in both groups, were positively correlated with Aβ42 and cognitive function, though only in women. The area under the ROC curve was 0.673 (95% CI:0.57-0.78) for serum adiponectin as predictor of dementia stage and the cut-off 10.85μg/ml maximized the sum of specificity (87%) and sensitivity (44%). Conclusion:Although longitudinal studies are required, we hypothesize that higher serum adiponectin in AD patients constitutes a strategy to compensate possible central signaling defects. In addition, adiponectin might be specifically assigned to neuroprotective functions in women and eventually involved in the female-biased incidence of Alzheimer’s disease.
