Magnetic Properties of Iron Oxides in the Human Globus pallidus

Iron, as the most abundant transition metal in the human brain, occurs with uneven distribution. Highest concentration of iron can be observed in areas associated with motor function (Globus pallidus, putamen, Substantia nigra) than in other areas of the human brain. Therefore, the actual role of iron accumulation in brain pathobiology isan active area of investigation nowadays.It is evident that amount of iron in brain gradually grows with age. Accumulation of iron in basal ganglia is probably associated with neuronal death leading to Alzheimer disease, Parkinson disease, epilepsy, Huntington disease, dementia with Lewy bodies, and multiple sclerosis. It was reported that iron participates in redox reactions, and catalyzes the formation of reactive oxygen species responsible for oxidative stress and damaging processes.

Iron in the human brain can be found mostly in the form of ferritin, hemosiderin (a product of ferritin breakdown) and other biomineralized oxidohydroxides and oxides such as hematite, magnetite, and maghemite. Ferritin, as an iron storage nonheme-protein with diameter up to 12 nm, consist of inorganic core (6 nm) formed of ferrihydrite and minor portion of magnetite and hematite that is enclosed by two types of polypeptides. The role of the heavy (Ft-H) form polypeptide coat of ferritin is to catalyze Fe(II) to Fe(III) ions whereas the light (Ft-L) polypeptide coat promotes the formation of ferritin iron core.The amount of Ft-H and Ft-L polypeptide coats changes during ageing and the magnetic properties of ferritin can also alter.(Read More)