High-Resolution Diffusion and Relaxation-Edited Magic Angle Spinning 1H NMR Spectroscopy of Intact Liver Tissue

Abstract

High-resolution magic angle spinning (HRMAS) 1H NMR spectroscopy is ideal for monitoring the metabolic environment within tissues, particularly when spectra are weighted by physical properties such as T 1 and T2 relaxation times and apparent diffusion coefficients (ADCs). In this study, spectral-editing using T1 and T2 relaxation times and ADCs at variable diffusion times was used in conjunction with HRMAS 1H NMR spectroscopy at 14.1 T in liver tissue. To enhance the sensitivity of ADC measurements to low molecular weight metabolites a T2 spin echo was included in a standard stimulated gradient spin-echo sequence. Fatty liver induced in rats by chronic orotic acid feeding was investigated using this modified sequence. An increase in the combined ADC for the co-resonant peaks glucose, betaine, and TMAO during fatty liver disease was detected (ADCs = 0.60 ± 0.11 and 0.35 ± 0.1 * 10-9 m2s-1 (n = 3) for rats fed with and without orotic acid), indicative of a reduction in glucose and betaine and an increase in TMAO. © 2003 Wiley-Liss, Inc.