Exogenous Agents as Drivers of Neurodegeneration: From Pharmaceuticals and Natural Toxins to Nanoparticles — A One Health Perspective

Neurodegenerative diseases (NDs) such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis represent a growing global health issue. Although addressed in a genetic context, current literature indicates that ND cases are influenced by exogenous and environmental factors as well. In this review we examine the neurotoxic potential of widely encountered external agents grouped into three categories: pharmaceutical compounds (antimicrobials, anesthetic agents, and benzodiazepines), naturally occurring plant and fungal toxins (including cyanogenic glycosides, excitotoxic amino acids, tryptamine alkaloids, swainsonine, and mycotoxins), and nanoparticles. This article presents the possible role of certain environmental toxins in neurodegenerative diseases in light of literature-based information, relating to human clinical and epidemiological studies within the one health concept, as well as studies involving pet and experimental animal models.