Ironing-Out Mechanisms of Neuronal Injury under Hypoxic–Ischemic Conditions and Potential Role of Iron Chelators as Neuroprotective Agents

Iron is the most abundant transition metal in the brain, where it functions as an important cofactor in a host of vital metabolic processes and plays an absolutely essential role in cell viability. Free iron is also very toxic when present in high concentrations, thus placing this essential metal at the core of neurotoxic injury in a number of neurological disorders. The pivotal role of iron in cellular homeostasis, including its latent toxicity, necessitates a tight regulation of iron metabolism. Oxygen and iron appear to play an important role in iron homeostasis. They appear to exert their homeostatic role by modulating the proteins involved in a complex interplay between iron sensing, transport, and storage. These key regulatory proteins include ferritin (intracellular storage), transferrin (extracellular transport), transferrin receptor, and iron regulatory protein (sensor of intracellular iron concentration). The interplay of iron and oxygen is most intriguing in the setting of stroke, where hypoxia and free iron appear to interact in causing the subsequent neuronal death.