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Characterisation of mobile lipid resonances in tissue biopsies from patients with cervical cancer and correlation with cytoplasmic lipid droplets
Author(s) -
Zietkowski D.,
deSouza N. M.,
Davidson R. L.,
Payne G. S.
Publication year - 2013
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.2923
Subject(s) - chemistry , nile red , cervical cancer , magic angle spinning , nuclear magnetic resonance , pathology , cancer , analytical chemistry (journal) , nuclear magnetic resonance spectroscopy , medicine , chromatography , physics , organic chemistry , quantum mechanics , fluorescence
The aims of this study were to characterise the major saturated and unsaturated lipid peaks in histologically normal cervical epithelium and stroma, dysplastic epithelium (low‐grade cervical intraepithelial neoplasia, CIN) and cancer‐containing tissue samples from patients with cervical cancer using diffusion‐weighted 1 H high‐resolution magic angle spinning MRS, to determine whether mobile lipid resonances (MLRs) distinguish tissue types and to test for a correlation between MLRs and the number of cytoplasmic lipid droplets. Diffusion‐weighted spectra of tissue biopsies were acquired using a stimulated echo sequence with bipolar gradients. Major saturated and unsaturated MLRs were identified and multivariate analysis of peak combinations was used to determine the best separation between tissue classes. Lipid droplets were visualised with Nile red staining and fluorescence microscopy. Correlations of saturated lipid resonances (0.9 and 1.3 ppm), polyunsaturated resonances (2.8 ppm), triglycerides (4.3 ppm) and unsaturated resonances (5.3 ppm) with average droplet number (per image) were investigated using a Spearman rank test. A large heterogeneity in lipid content among samples was observed, resulting in no significant differences in MLR intensities of individual peaks between the three tissue classes. Linear discriminant analysis separated ‘no cancer’ from ‘cancer’ based on the intensities at 0.9, 1.3, 2.2 and 2.8 ppm [area under the curve (AUC) = 0.939, p < 0.001], ‘low‐grade CIN’ from ‘cancer’ based on the intensities at 0.9, 4.1, 4.3 and 5.3 ppm (AUC = 0.987, p < 0.001) and ‘no cancer’ from ‘low‐grade CIN’ based on intensities at 0.9, 2.2 and 4.3 ppm (AUC = 0.984, p < 0.001). The distribution of cytoplasmic lipid droplets was nonuniform and was not related to the presence of epithelial or stromal components. On average, there were more droplets visible in low‐grade CIN and cancer‐containing tissues. Significant correlations between MLR peaks and lipid droplet number were seen for 0.9 ( p = 0.002), 1.3 ( p = 0.003) and 2.8 ppm ( p = 0.018). MLR combinations indicative of average lipid structure efficiently separated tissue classes. Increased lipid resonances correlated with increased numbers of cytoplasmic lipid droplets. Copyright © 2013 John Wiley & Sons, Ltd.