While the demand for metabolic imaging has increased in recent years, simultaneous in vivo measurement of multiple metabolic endpoints remains challenging. Here we report on a novel technique that provides in vivo high-resolution simultaneous imaging of glucose uptake and mitochondrial metabolism within a dynamic tissue microenvironment. Two indicators were leveraged; 2-[N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG) reports on glucose uptake and Tetramethylrhodamine ethyl ester (TMRE) reports on mitochondrial membrane potential. Although we demonstrated that there was neither optical nor chemical crosstalk between 2-NBDG and TMRE, TMRE uptake was significantly inhibited by simultaneous injection with 2-NBDG in vivo. A staggered delivery scheme of the two agents (TMRE injection was followed by 2-NBDG injection after a 10-minute delay) permitted near-simultaneous in vivo microscopy of 2-NBDG and TMRE at the same tissue site by mitigating the interference of 2-NBDG with normal glucose usage. The staggered delivery strategy was evaluated under both normoxic and hypoxic conditions in normal tissues as well as in a murine breast cancer model. The results were consistent with those expected for independent imaging of 2-NBDG and TMRE. This optical imaging technique allows for monitoring of key metabolic endpoints with the unique benefit of repeated, non-destructive imaging within an intact microenvironment.
|State||Published - Dec 1 2017|
Bibliographical noteFunding Information:
This work was supported by generous funding from the Department of Defense Era of Hope Scholar Award (http://cdmrp.army.mil/bcrp/era; W81XWH-09-1-0410). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We would like to thank Dr. Fan Yuan for his helpful discussion on our 2-NBDG and TMRE imaging data. We would like to thank Dr. Alaattin Erkanli for his assistance in selecting the statistical tests for our data analysis. We also would like to thank Megan C. Madonna, Marianne Lee and Helen A. Murphy for their assistance during the animal imaging. Many thanks to Dr. Jenna H. Mueller, Dr. Fangyao Hu, and Christopher T. Lam and for their generous help with the imaging system development.
© 2017 The Author(s).
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