Poster abstracts
Poster number 1 submitted by Kevin Walsh
Magnetic Mapping of Iron in Brain Tissue from Alzheimer’s Disease
Kevin Walsh (Biophysics Program, The Ohio State University), Stavan Shah (Department of Biomedical Engineering, The Ohio State University), Ping Wei (Department of Neuroscience, The Ohio State University), Sam Oberdick (Physics Department, University of Colorado, Boulder), Dana McTigue (Department of Neuroscience, The Ohio State University), Gunjan Agarwal (Department of Mechanical and Aerospace Engineering, The Ohio State University)
Abstract:
Iron (Fe) is an essential metal involved in a wide spectrum of physiological functions in the body, such as oxygen transport and enzymatic reactions. The oxidation state, mineral composition and storage of iron play a crucial role in health and disease. Several neurodegenerative diseases, including Alzheimer’s Disease (AD), are characterized by tissue iron deposits which can differ in size and composition from physiological iron deposits. Histochemical staining, the routinely used approach to characterize iron distribution, offers limited insight into the chemical environment and composition of tissue iron. One of the properties of iron which has not been adequately exploited in histology is the magnetic behavior of tissue iron. In this study, coronal slices of the left hemisphere of AD brain samples were examined by magnetic resonance imaging (MRI) to map iron deposits via their magnetic signatures (T2 and T2*). Perl’s histochemical staining and immunohistochemical staining for microglia were used to map the spatial distribution of ferric iron (Fe3+) in highly effected areas associated with AD, namely the inferior temporal gyrus and hippocampus. Adjacent, unstained sections were analyzed via magnetic force microscopy (MFM), an atomic force microscopy (AFM)-based technique. Finally, hippocampus samples that underwent MFM analysis, were subjected to scanning electron microscopy with electron dispersion x-ray spectroscopy (SEM-EDS) to correlate the physical size and chemical composition of iron deposits found in MFM images. These results provide novel insights into the distribution of iron in AD brain tissue. Further studies along these directions can allow for better interpretation of the quantity and quality of iron in AD as well as other pathologies.
References:
Blissett, A. R., Deng, B., Wei, P., Walsh, K. J., Ollander, B., Sifford, J., Sauerbeck, A. D., McComb, D. W., McTigue, D. M., & Agarwal, G. (2018). Sub-cellular In-situ Characterization of Ferritin(iron) in a Rodent Model of Spinal Cord Injury. Scientific Reports, 8(1), 3567.
Walsh, K. J., Shah, S. V., Wei, P., Oberdick, S. D., Dickson-Karn, N. M., McTigue, D. M., & Agarwal, G. (2020). Effects of fixatives on histomagnetic evaluation of iron in rodent spleen. Journal of Magnetism and Magnetic Materials, 521(P1), 167531. https://doi.org/10.1016/j.jmmm.2020.167531
Keywords: magnetic force microscopy, iron, Alzheimers disease