Down syndrome (DS) is the most common genetic disorder characterized by an extra copy of chromosome 21. DS subjects show signs of progressive cognitive decline, and most of them develop Alzheimer's type dementia at the age of 50 to 55 years. The aim of this study was to evaluate amyloid precursor protein (APP) metabolites and anti-Abeta 1-42 antibodies plasma levels in DS as possible biomarkers of Abeta accumulation potentially leading to neurodegeneration. We investigated plasma levels of sAPPα, Abeta 1-42, and anti-Abeta 1-42 antibodies by enzyme-linked immunosorbent assay in 24 DS subjects, 10 non-DS mentally retarded subjects and 18 age-matched controls. We found that sAPPα levels were about 1.5-fold higher and Abeta 1-42 levels were about 6-fold higher in DS respect to mentally retarded patients and to controls. DS patients showed Abeta 1-42 antibodies levels 4-fold higher than non-DS mentally retarded group and 2-fold higher than controls. Moreover, anti-Abeta 1-42 antibodies levels were inversely correlated with age in DS subjects. Our results suggested sAPPα as a possible peripheral marker for the alteration in APP metabolism in DS and highlighted an alteration in anti-abeta antibodies, for the first time evaluated in plasma from DS subjects.
*Department of Neuroscience and Biomedical Technologies, San Gerardo Hospital, University of Milano-Bicocca, Monza (MI)
†Scientific Institute IRCCS “E.Medea,” Bosisio Parini (LC), Italy
Supported by grant PS/03/4 (Ricerca finalizzata 2004) and 0021310 (Ricerca finalizzata 2005) from Italian Ministry of Health.
Reprints: Gloria Galimberti, PhD, Department of Neuroscience and Biomedical Technologies, San Gerardo Hospital, University of Milano-Bicocca, Via Cadore 48, 20052 Monza (MI), Italy (e-mail: email@example.com).
Received for publication September 30, 2008
accepted April 7, 2009