Redox Homeostasis in Red Blood Cells: From Molecular Mechanisms to Antioxidant Strategies.

Red blood cells (RBCs) are uniquely vulnerable to oxidative stress due to their role in O2 transport and their high content of heme iron and polyunsaturated fatty acids (PUFAs). Despite lacking nuclei and organelles, RBC homeostasis relies on a finely tuned redox system to preserve membrane integrity, cytoskeletal organization, and metabolic function. Impairment of this delicate balance results in a series of oxidative events that ultimately leads to the premature clearance of RBCs from the bloodstream. This review outlines the main oxidative mechanisms that affect RBC at different levels, such as membrane, cytoskeleton, and intracellular environment, with a focus on the molecular targets of reactive species. The role of major antioxidant systems in preventing or reversing redox damage will also be examined, revealing their multiple mechanisms of action ranging from direct ROS scavenging to the enhancement of endogenous antioxidant defense pathways. Redox regulatory mechanisms in RBCs are required to maintain membrane integrity, cytoskeletal organization, and metabolic function. Disruption of these processes causes several oxidative processes that trigger premature RBC removal. Cumulative evidence places oxidative stress at the core of RBC dysfunction in both physiological aging and pathological conditions, including diabetes, inflammatory conditions, and hemolytic disorders. Antioxidant-based strategies, rather than providing generalized protection, should aim to selectively target the specific molecular pathways affected in distinct clinical settings.