Brem, Franziska; Hirt, Ann M.; Winklhofer, Michael; Frei, Karl; Yonekawa, Yasuhiro; Wieser, Heinz-Gregor; Dobson, Jon
Magnetic iron compounds in the human brain: a comparison of tumour and hippocampal tissue.
In: Journal of the Royal Society Interface, Vol. 3, No. 11: pp. 833-841
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Iron is a central element in the metabolism of normal and malignantcells. Abnormalities in iron and ferritin expression have been observedin many types of cancer. Interest in characterizing iron compounds inthe human brain has increased due to advances in determining arelationship between excess iron accumulation and neurological andneurodegenerative diseases. In this work, four different magneticmethods have been employed to characterize the iron phases and magneticproperties of brain tumour (meningiomas) tissues and non-tumourhippocampal tissues. Four main magnetic components can be distinguished:the diamagnetic matrix, nearly paramagnetic blood, antiferromagneticferrihydrite cores of ferritin and ferrimagnetic magnetite and/ormaghemite. For the first time, open hysteresis loops have been observedon human brain tissue at room temperature. The hysteresis propertiesindicate the presence of magnetite and/or maghemite particles thatexhibit stable single-domain (SD) behaviour at room temperature. Asignificantly higher concentration of magnetically ordered magnetiteand/or maghemite and a higher estimated concentration of heme iron wasfound in the meningioma samples. First-order reversal curve diagrams onmeningioma tissue further show that the stable SD particles aremagnetostatically interacting, implying high-local concentrations(clustering) of these particles in brain tumours. These. ndings suggestthat brain tumour tissue contains an elevated amount of remanent ironoxide phases.