ORIGINAL ARTICLE Ethanol Reduces Amyloid Aggregation In Vitro and Prevents Toxicity in Cell Lines David Orme~ no, a,b Fernando Romero, b Julio L opez-Fenner, c  Andres Avila, c Ataulfo Mart  ınez-Torres, d and Jorge Parodi e a Laboratorio de Fisiolog ıa de la Reproducci on, N ucleo de Investigaci on en Producci on Alimentaria, Facultad de Recursos Naturales, Escuela de Medicina Veterinaria, Universidad Cat olica de Temuco, Temuco, Chile b Laboratorio de Neurociencia, BIOREN-CEBIOR, Departamento de Ciencias Preclinicas, Facultad de Medicina, Universidad de la Frontera, Temuco, Chile c Centro de Excelencia de Modelaci on y Computaci on Cient  ıfica, Facultad de Ingenier  ıa, Ciencias y Administraci on, Universidad de La Frontera, Temuco, Chile d Laboratorio de Neurobiolog ıa Molecular y Celular, Departamento de Neurobiolog ıa Celular y Molecular, Instituto de Neurobiolog ıa, Campus Juriquilla-Quer etaro, UNAM, M exico e Laboratorio de Simulaci on MoleculareCEMCC, Universidad de la Frontera, Temuco, Chile Received for publication June 21, 2012; accepted December 6, 2012 (ARCMED-D-12-00314). Background. Alzheimer’s disease (AD) alters cognitive functions. A mixture of soluble b-amyloid aggregates (Ab) are known to act as toxic agents. It has been suggested that moderate alcohol intake reduces the development of neurodegenerative diseases, but the molecular mechanisms leading to this type of prevention have been elusive. We show the ethanol effect in the generation of complex Ab in vitro and the impact on the viability of two cell lines. Methods. The effect of ethanol on the kinetics of b-amyloid aggregation in vitro was assessed by turbimetry. Soluble- and ethanol-treated b-amyloid were added to the cell lines HEK and PC-12 to compare their effects on metabolic activity using the MTT (3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. In addition, we used molecular modeling to assess the impact of exposure to ethanol on the structure of b-amyloid. Results. Exposure to soluble b-amyloid was toxic to both cell lines; however, exposing the cells to b-amyloid aggregated in 10 mmol ethanol prevented the effect. In silico modeling suggested that ethanol alters the dynamics for assembling Ab by disrupting a critical salt bridge between residues Asp 23 and Lys 28, required for amyloid dimeriza- tion. Thus, ethanol prevented the formation of complex short (|100 nm) Ab, which are related to higher cell toxicity. Conclusions. Ethanol prevents the formation of stable Ab dimers in vitro, thus protecting the cells maintained in culture. Accordingly, in silico modelling predicts that soluble b-amyloid molecules do not form stable multimers when exposed to ethanol. Ó 2013 IMSS. Published by Elsevier Inc. Key Words: Alzheimer’s disease, b-amyloid, Ethanol, Molecular simulation. Introduction Alzheimer’s disease (AD) is a pathology with high social impact and is considered a health problem of global dimensions (1,2). The triggering agent for this disease is formed by aggregates of b-amyloid (Ab) which, according to recent evidence, are soluble amyloid oligomers that generate the first symptoms of the disease (3). It has been established that molecules of Ab lock on the synapses (4), alter the response of cholinergic and NMDA receptors (5), recycle synaptic vesicles (6,7), have widespread effects on synaptic activity in general (8), and participate in Ab in modifying long-term potentiation in hippocampus (9). In Address reprint requests to: Jorge Parodi, Laboratorio de Fisiolog  ıa de la Reproducci on, N ucleo de Investigaci on en Producci on Alimentaria, Facultad de Recursos Naturales, Escuela de Medicina Veterinaria, Campus Norte, Rudecindo Ortega 02950, Universidad Cat olica de Temuco, Temuco, Chile; Phone and Fax: 56-45-205564; E-mail: jparodi@uct.cl 0188-4409/$ - see front matter. Copyright Ó 2013 IMSS. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.arcmed.2012.12.004 Archives of Medical Research 44 (2013) 1e7