Cerium oxide nanoparticles: a promising nanotherapy approach for chronic degenerative diseases

Abstract Oxidative stress is a process caused by excess-free radicals and reactive oxygen species (ROS), which contribute to the onset and progression of various chronic degenerative diseases. Consequently, interest has grown in studying natural and synthetic antioxidant compounds that restore normal ROS metabolism, alleviating the damage in affected tissues. Despite the above, several preclinical and clinical studies evaluating these therapies have shown some contradictory results since sometimes the use of these molecules has not shown the desired therapeutic efficacy, or in some cases, the use of these antioxidants has been related to the appearance of harmful effects due to their lack of specificity, to the associated adverse effects, in addition to the fact that some ROS are essential for normal physiological functions. On the other hand, nanotechnology is one of the most widely used technological advances in the drug industry. Targeted delivery of active ingredients combines knowledge of pharmacology, pharmaceutical development, polymer sciences, conjugate chemistry, and molecular biology to improve the pharmacokinetics of active ingredients, decreasing their toxicity, immunogenicity, and biorecognition. Cerium oxide nanoparticles (CeO 2 -NPs) have emerged as a novel therapeutic alternative with high antioxidant capacity, demonstrating beneficial effects in both in vivo and in vitro studies for treating chronic degenerative disorders. CeO 2 -NPs are only activated when ROS levels reach a harmful threshold, which protects healthy cells from unwanted effects. Their therapeutic potential has been demonstrated in multiple fields of medicine, including oncology, neurology, ophthalmology, cardiology, and hepatology. Therefore, this review addresses the potential applications of CeO 2 -NPs evaluated in animal and in vitro models of chronic degenerative diseases, which help visualize and position them as an effective and safe therapeutic alternative for treating this condition.