Brain iron acquisition: An overview of homeostatic regulation and disease dysregulation

Brain iron homeostasis is crucial for neurological health, with pathological fluctuations in brain iron levels associated with a variety of neurological disorders. Low levels are connected to cognitive impairment and restless legs syndrome, while high levels are connected to Alzheimer's disease, Parkinson's disease, and other neurodegenerative diseases. Given the detrimental effects unrestricted iron can have, regulated entry into the brain via transferrin and H-ferritin is critical. Endothelial cells of the blood-brain barrier are the site of iron transport regulation. The movement of iron through endothelial cells into the brain can be divided into three distinct processes: uptake, transcytosis, and release. Each process possesses external and internal influences on the regulation at each stage. This review discusses the mechanisms of iron uptake, transcytosis, and release at the blood-brain barrier, as well as the elements that contribute to regulation. Additionally, we explore the dysregulation of brain iron in Alzheimer's disease, Parkinson's disease, and restless legs syndrome.