Free radicals in Alzheimer's disease: From pathophysiology to clinical trial results.

In this review, we examine the role of oxidative stress in the pathophysiology of Alzheimer's Disease (AD). Amyloid-beta (Aβ) induces damage not only extracellularly but also within the intracellular environment. Mitochondria, a principal source of free radicals, are closely associated with Aβ, as it binds to heme, thereby disrupting the normal electron flow in the respiratory chain. At the turn of the century, it was hypothesized that the majority, if not all, pathological events in AD are linked to free radical damage. Notably, free radicals also possess signaling capabilities that contribute to the disease's progression. A substantial body of evidence suggests that radical signaling is implicated in the relationship between amyloid-β and tau hyperphosphorylation. Antioxidant therapy represents a potential strategy to delay the progression from cognitive impairment to overt dementia. Enhancing endogenous antioxidant defenses, for instance, through polyphenol supplementation, offers a promising approach to partially prevent dementia onset, particularly in at-risk populations. Understanding the redox-related pathophysiology of AD opens new avenues for prevention and treatment, providing a source of hope in the fight against Alzheimer's Disease.