Metabolite identification in human liver needle biopsies by high-resolution magic angle spinning1H NMR spectroscopy

Abstract

High-resolution magic angle spinning (HR-MAS) 1H NMR spectroscopy of intact human liver needle biopsies has not been previously reported. HR-MAS NMR spectra collected on 17 specimens with tissue amounts between approximately 0.5 and 12 mg showed very good spectral resolution and signal-to-noise ratios. One-dimensional 1H spectra revealed many intense signals corresponding to cellular metabolites. In addition, some high molecular weight metabolites, such as glycogen and mobile fatty acids, could be observed in some spectra. Resonance assignments for 22 metabolites were obtained by combining the analysis of three different types of 1D 1H spectral editing, such as T2 filtering or the nuclear Overhauser effect and 2D TOCSY and 13C-HSQC spectra. Biochemical stability of the liver tissue during up to 16 h of magic angle spinning at 277 K was studied. Biochemical trends corresponding to the different pathologies were observed, involving free fragments of lipids among other metabolites. NMR signal intensity ratios can be useful for discrimination among non-pathological, hepatitis C affected and cirrhotic liver tissues. Overall, this work demonstrates the applicability of HR-MAS NMR spectroscopy to the biochemical characterization of needle biopsies of the human liver.

Metabolic profile of chronic liver disease by NMR spectroscopy of human biopsies

“…High resolution magic angle spinning (HR-MAS) NMR spectroscopy is a powerful technique for the investigation of metabolites within different intact tissues (25)(26)(27)(28)(29)(30)(31). The precise determination of the biochemical and metabolic profiles in intact tissue promises to extend the possibilities of NMR as a medical diagnostic tool.…”

“…Although it has some minor limitations associated mainly to the spinning of the sample (spinning side-bands, spinning degradation effects and spinning temperature gradients among others), HR-MAS NMR is a non-destructive technique, which requires minimal sample preparation, and allows the observation of most of the tissue metabolites and dynamic interactions in an extremely reduced sample quantity. This technology can supplement histopathological examination and improve liver disease diagnostics (21,28,36,37). The similarities between 'ex vivo' and 'in vivo' spectra found in studies of different tumours allow better interpretation of in vivo MR spectra and increase the clinical potential of the method (38).…”

“…This approach can be used to define the metabolomic phenotype of a tissue. Previous studies have shown the potential of HR-MAS NMR spectroscopy as a tool for liver disease characterization (21,28,36). Furthermore, studies in human liver tissue suggested the applicability of the technique in the assessment of liver transplant viability (36).…”

Use of 1H and 31P HRMAS to evaluate the relationship between quantitative alterations in metabolite concentrations and tissue features in human brain tumour biopsies

“…There is a widespread use of 1 H 1D spectra to quantify the metabolites [1-3, 6, 7]. 2D 1 H -1 H homonuclear or 1 H - 13 C heteronuclear experiments have improved the assignments in HRMAS spectra [3][4][5]8] but the quantitative metabolic information comes mainly from the 1 H 1D spectra. The use of 31 P NMR spectroscopy has also been demonstrated to be useful in the metabolomic study of brain cancer since there are 31 P-containing metabolites that can provide valuable information complementary to 1 H NMR in metabolic studies [9][10][11].…”

Current and future applications ofin vitromagnetic resonance spectroscopy in hepatobiliary disease

“…Differences in signal intensities between disease states and "normal" liver were noted, particularly increases in mobile fatty acids and glycogen in the former. However, the "normal" liver was harvested 24 h post mortem, so assumptions of metabolic normality are questionable [30] .…”