Is Amyloid-β an Innocent Bystander and Marker in Alzheimer's Disease? Is the Liability of Multivalent Cation Homeostasis and its Influence on Amyloid-β Function the Real Mechanism?

Article type: Research Article

Authors: ManafiRad, Arash^a | Farzadfar, Farshad^b | Habibi, Laleh^c | Azhdarzadeh, Morteza^c | Aghaverdi, Haniyeh^d | Tehrani, Khadijeh H.^d | Lotfi, Mina^c | Kehoe, Patrick G.^e | Sheidaei, Ali^f | Ghasemian, Anoosheh^b | Darzi, Ehsan Rezaei^b | Mahmoodi, Ramin^g | Mahmoudi, Morteza^{a; h; i; *}

Affiliations: [a] National Cell Bank, Pasteur Institute of Iran, Tehran, Iran | [b] Non-communicable Diseases Research Center, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran | [c] Nanotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran | [d] Department of Medicine, Islamic Azad University, Tehran, Iran | [e] Dementia Research Group, School of Clinical Sciences, University of Bristol, John James Laboratories, Frenchay Hospital, Bristol, UK | [f] Department of Biostatistics, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran | [g] International Neuroscience Institute, Hannover, Germany | [h] Department of Nanotechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran | [i] Current Address: Department of Pediatrics, Division of Cardiology, School of Medicine, Stanford University, Stanford, CA, USA

Correspondence: [*] Correspondence to: Morteza Mahmoudi, Tel.: +98 912 5791557; Fax: +98 21 22568051; E-mail: Mahmoudi@stanford.edu.

Abstract: Two decades of the amyloid-β (Aβ) hypothesis in Alzheimer's disease (AD) and the prominence of Aβ-targeting strategies have yet to meet the levels of original expectation. Disappointing results in numerous Phase II/III studies have called for a re-examination of the validity of the Aβ-targeting approaches as an intervention strategy in AD. The mid-life onset of chronic conditions (e.g., hypertension, diabetes, insulin intolerance, and depression nominated as risk factors for the later development of AD) points to the possibility that each condition could involve mechanisms, which while relatively modest over a short-term, could have significant accumulative effects. What may also not be fully appreciated is that a number of these conditions involve potential disturbances to multivalent cations (MC) levels through various mechanisms such as autophagy, oxidative stress, and apoptosis. Furthermore, some MCs have intimate associations with the mechanisms by which Aβ pathology manifests. Considering various lines of evidence and incorporating statistical analysis on Disability–Adjusted Life Years (DALYs) data of both causes of and prevalence of multifactorial risk factors in different world regions, we propose an MC hypothesis for AD. More specifically, we suggest that MC imbalance marks many chronic conditions and because of their involvement with Aβ pathology, could reflect that Aβ may be a vital manifestation and marker of underlying MC imbalance. Thus, careful targeting of MC imbalance may provide an alternative or complementary interventional approach to current Aβ treatment strategies.

Keywords: Alzheimer's disease, amyloid-β pathology, cellular integrity, chronic conditions, lifestyle, multivalent cations homeostasis, risk factors

DOI: 10.3233/JAD-140321

Journal: Journal of Alzheimer's Disease, vol. 42, no. 1, pp. 69-85, 2014