Nuclear magnetic resonance-based metabolomics of OCT-embedded frozen kidney samples in mouse and man following standardized pre-analytics

作者：Leenders Justine; Buemi Antoine; Mourad Michel; de Tullio Pascal; Jouret Francois^*

来源：Metabolomics, 2017, 13(8): 94.

DOI：10.1007/s11306-017-1232-9

• Metabolomics
• NMR
• OCT
• Kidney
• Ischemia/reperfusion
• Transplantation

Introduction Pre-analytical processing significantly affects tissue metabolomes. Since most frozen kidney samples are stored after embedding, standardization of cryoprotective medium removal before metabolomics is essential. Objectives We used rodent and human kidney samples to develop an easy and robust pre-analytical procedure compatible with H-1-nuclear magnetic resonance (NMR)-based metabolomics.
Methods In mice, renal ischemia was induced for 30 min, followed by 48-h reperfusion (I/R, n = 6). Right kidneys were transversally cut in two fragments, and snap-frozen in liquid nitrogen (LN2) or in Optimal Cutting Temperature (R) (OCT) fixative. In man, double kidney biopsies were simultaneously obtained before transplantation (n = 15), and snap-frozen in LN2 or OCT.
Results H-1-NMR spectrum of pure OCT highlighted two major peaks, i.e. from 3.4 to 4.2 ppm (47.2%) and from 1.2 to 2.2 ppm (42.5%). H-1-NMR spectra of mouse OCT of mouse OCT kidneys iteratively rinsed in saline significantly discriminated sham versus I/R groups, with Q(2) at 0.695 (to be compared with Q(2) at 0.866 for LN2 sham vs. I/R kidneys). Discriminant metabolites were analogous in both OCT and LN2 kidneys, with a correlation coefficient of 0.83. In man, iteratively rinsing OCT kidneys in saline eliminated the spectral 3.7-peak, thereby making metabolomes of OCT kidneys interpretable and similar to LN2 samples, with a correlation coefficient of 0.73.
Conclusion NMR metabolomics using OCT-frozen kidney samples is valuable in mouse and man, following standardized OCT removal. This may help use residual biobanked human tissues to better understand renal pathophysiology.

• 出版日期2017-8