Abstract by Isabella James
Chemistry and Biochemistry
Desorption Electrospray Ionization mass spectrometry imaging of lipid metabolism in Alzheimer’s disease
DESI (desorption electrospray ionization) can be used in combination with metabolic deuterium labeling to produce an image of lipid turnover rates in different areas of the brain. This is done by feeding mice deuterated water and taking brain scans at different time points to measure the deuterium incorporated into different lipids. We have attached our lab-constructed DESI setup to an Agilent QToF for fragmentation data, allowing us to confirm our identification of lipids. For higher resolution scans, we use the DESI setup with an Orbitrap. The strongest genetic risk factor for Alzheimer’s Disease (AD), are mutations to the APOE lipid transport protien. The APOE4 isoform combined with high levels of cholesterol results in a high risk factor for AD. Imaging cholesterol requires a reactive DESI technique due to its low proton affinity. We use positive ion mode with the addition of betaine aldehyde to the solvent to react with the cholesterol. We have used our DESI source to image normal mouse brains and determine lipid standards. With our experience, we are prepared to investigate AD, which can be viewed as a change in lipid metabolism, specifically cholesterol.