title: A novel approach to quantify different iron forms in ex-vivo human brain tissue.
abstract: We propose a novel combination of methods to study the physical properties of ferric ions and iron-oxide nanoparticles in post-mortem human brain, based on the combination of Electron Paramagnetic Resonance (EPR) and SQUID magnetometry. By means of EPR, we derive the concentration of the low molecular weight iron pool, as well as the product of its electron spin relaxation times. Additionally, by SQUID magnetometry we identify iron mineralization products ascribable to a magnetite/maghemite phase and a ferrihydrite (ferritin) phase. We further derive the concentration of magnetite/maghemite and of ferritin nanoparticles. To test out the new combined methodology, we studied brain tissue of an Alzheimer's patient and a healthy control. Finally, we estimate that the size of the magnetite/maghemite nanoparticles, whose magnetic moments are blocked at room temperature, exceeds 40-50 nm, which is not compatible with the ferritin protein, the core of which is typically 6-8 nm. We believe that this methodology could be beneficial in the study of neurodegenerative diseases such as Alzheimer's Disease which are characterized by abnormal iron accumulation in the brain.
authors.affiliation: Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands.
authors.forename: Pravin
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.|Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Marjolein
authors.initials: M
authors.lastname: Bulk
authors.affiliation: Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Andrew
authors.initials: A
authors.lastname: Webb
authors.affiliation: Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.|Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Louise
authors.initials: L
authors.lastname: van der Weerd
authors.affiliation: Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands.
authors.forename: Tjerk H
authors.initials: TH
authors.lastname: Oosterkamp
authors.affiliation: Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands.
authors.forename: Martina
authors.initials: M
authors.lastname: Huber
authors.affiliation: Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands.
authors.forename: Lucia
authors.initials: L
authors.lastname: Bossoni
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism*; D001923:Brain Chemistry; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005260:Female; D005290:Ferric Compounds / Q000737:chemistry*; D006801:Humans; D007501:Iron / Q000737:chemistry*; D060328:Magnetic Phenomena; D058185:Magnetite Nanoparticles; D060306:Magnetometry / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide; D007501:Iron