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Correlation of hyperpolarized 13 C‐MRI data with tissue extract measurements
Author(s) -
Lee Casey Y.,
Lau Justin Y. C.,
Geraghty Benjamin J.,
Chen Albert P.,
Gu YiPing,
Cunningham Charles H.
Publication year - 2020
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.4269
Subject(s) - lactate dehydrogenase , in vivo , ex vivo , chemistry , lactate dehydrogenase a , isotopomers , pyruvic acid , nuclear magnetic resonance , biochemistry , in vitro , biology , enzyme , physics , microbiology and biotechnology , organic chemistry , molecule
Hyperpolarized (HP)13 C MRI provides the means to monitor lactate metabolism noninvasively in tumours. Since13 C ‐lactate signal levels obtained from HP13 C imaging depend on multiple factors, such as the rate of13 C substrate delivery via the vasculature, the expression level of monocarboxylate transporters (MCTs) and lactate dehydrogenase (LDH), and the local lactate pool size, the interpretation of HP13 C metabolic images remains challenging. In this study, ex vivo tissue extract measurements (i.e., NMR isotopomer analysis, western blot analysis) derived from an MDA‐MB‐231 xenograft model in nude rats were used to test for correlations between the in vivo13 C data and the ex vivo measures. The lactate‐to‐pyruvate ratio from HP13 C MRI was strongly correlated with [1‐13 C ]lactate concentration measured from the extracts using NMR ( R = 0.69, p < 0.05), as well as negatively correlated with tumour wet weight ( R = − 0.60, p < 0.05). In this tumour model, both MCT1 and MCT4 expressions were positively correlated with wet weight ( ρ = 0.78 and 0.93, respectively, p < 0.01). Lactate pool size and the lactate‐to‐pyruvate ratio were not significantly correlated.