Glucose metabolism studied by low Energy XRF

Glucose metabolism is difficult to image with cellular resolution in mammalian brain tissue, particularly with 18fluorodeoxy-D-glucose (FDG) positron emission to- mography (PET). To this end, we explored the potential of synchrotron-based low-energy X-ray fluorescence (LEXRF) to image the stable isotope of fluorine (F) in phosphorylated FDG (DG-6P) at 1 um2 spatial resolution in 3 um-thick brain slices. The excitation-dependent fluorescence F signal at 676 eV varied linearly with FDG concentration between 0.5 and 10 mM, whereas the en- dogenous background F signal was undetectable in brain.

To validate LEXRF mapping of fluorine, FDG was administered in vitro and in vivo, and the fluorine LEXRF signal from intracellular trapped FDG-6P over selected brain areas rich in radial glia was spectrally quantitated at 1 lm2 resolution. The subsequent generation of spatial LEXRF maps of F reproduced the expected localization and gradients of glucose metabolism in retinal Mueller glia. In addition, FDG uptake was localized to periventric-ular hypothalamic tanycytes, whose morphological features were imaged simultaneously by X-ray absorption. We conclude that the high specificity of photon emission from F and its spatial mapping at 1 um resolution demonstrates the ability to identify glucose uptake at subcellular resolution and holds remarkable potential for imaging glucose metabolism in biological tissue.

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Feasibility of Direct Mapping of Cerebral Fluorodeoxy-D-Glucose Metabolism In Situ at Subcellular Resolution Using Soft X-Ray Fluorescence;
C. Poitry-Yamate, A. Gianoncelli, B. Kaulich, G. Kourousias, A.W. Magill, M. Lepore, V. Gajdosik, R. Gruetter;

Journal of Neuroscience Research 2012.

Ultima modifica il Domenica, 21 Aprile 2013 20:17