The Role of Oxidative Stress in Aging and Dementia

Abstract

Introduction: Biologic aging is a process, and oxidative stress theory, which is one of the most accepted biological theories for aging, states that oxidative stress causes cumulative damage to mitochondrial DNA resulting in cellular senescence. Dementia is a neurodegenerative disorder whose major risk factor is aging. Although the exact neuronal lesion mechanisms underlying neurodegenerative disorders, including dementia, are not yet known, most recent studies suggest oxidative stress and mitochondrial dynamics’ role in the process.

Objective: Literature review on the role of oxidative stress’ role in aging and dementia.

Methods: Literature review of selected arti-cles and books deemed relevant by the authors, supplemented by Medline/Pubmed database search using combinations of the following key-words: “oxidative stress”, “de-mentia”, “aging” and “pathogenesis”, published between 1950 and 2013. References of the selected articles and books were also considered.

Results: In the last five years new research has been undertaken that enlightens the relation between oxidative stress and aging. One of the considered hypotheses states that during aging, the homeostatic regulation of biogenesis, dynamics and autophagic turnover of mitochondria disturbs their functioning, resulting in cellular senescence. Consequently, the oxidative burden may reach a critical threshold above which apoptosis is triggered, leading to irreversible mitochondrial derangement and cellular death. Although the exact neuronal lesion mechanisms underlying dementias are not known, multiple studies have consistently found increased oxidative damage in brain of patients with Alzheimer disease and recent data suggests involvement of mitochondrial dynamics in dementia processes, such as in aging.

Conclusions: Most recent studies suggest the role of oxidative stress and mitochondrial dynamics’ in aging and dementia, either directly or by indirect pathways, which can influence future perspectives about the pathophysiology of dementia and open new treatment options.