MSACL 2019 EU Abstract

Graft Quality Assessment in Kidney Transplantation by Monitoring Lipidomic Changes in the Organ During Transplantation Using Solid Phase Microextraction (SPME)

Natalia Warmuzińska(1), Iga Stryjak(1), Kamil Łuczykowski(1), Joanna Bogusiewicz(1), Matyas Hamar(2), Markus Selzner(2,3), Barbara Bojko(1)
(1) Department of Pharmacodynamics and Molecular Pharmacology, Faculty of Pharmacy, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, Poland, (2) Multi Organ Transplant Program, Department of Surgery, Toronto General Hospital, University Health Network,Toronto Canada, (3) Department of Medicine, Toronto General Hospital Toronto, Toronto, Canada

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Natalia Warmuzińska (Presenter) Nicolaus Copernicus University in Toruń >> POSTER (PDF)

Relevant Financial Disclosures (within past 24 months) Grant/Research Support National Science Centre, Poland, grant 2017/27/B/NZ5/01013 Conflict mitigation NOT REQUIRED.

Introduction:Transplantology is one of the fastest growing area of medicine. However, it faces many serious problems, such as lack of effective tools for organ quality assessment. Since tissue biopsy is invasive and macroscopic visual assessment is unreliable, new technologies are strongly needed. A lipidomic approach is a possibility to better understanding the mechanism of reperfusion grafts injury and identify potential organ quality biomarkers.
Methods:Solid phase microextraction (SPME) was used for direct kidney sampling and as a sample preparation method. The study was performed on kidneys from two types of porcine model donors (n=6): heart beating donor (HBD) and donor after cardiac death (DCD). Sampling was performed as follow: in vivo before transplantation, in situ after 1h, 3h, 5h, 7h of perfusion, in vivo immediately after revascularization in the recipient, and additionally for DCD after 45 min and 2h of warm ischemia time. Chromatographic separation was done on RP and HILIC columns followed by detection on high resolution mass spectrometer (HRMS) operated in positive ionization mode. The statistical analysis was used to differentiate changes during organ preservation and to find dysregulated lipids, which could be potential biomarkers for organ injury.

Results:One-way Analysis of Variance (ANOVA) and post-hoc analyses were used for the comparison of the study groups. Statistically significant compounds were selected with p-value threshold 0,05. PCA and OPLS-DA plots were created in addition to ANOVA and post-hoc analyses. The results obtained from instrumental analysis together with biostatistical-based approach showed differentiation between samples harvested before and after transplantation. Results of unsupervised analysis indicated the difference in lipidomic profile between monitored time points e.g. HBD donor and reperfusion time point with PC1 describing 54% of the variation and PC2 describing 15.9%. Over 60 statistically significant features were identified for this comparison with the use of volcano plot (p<0.05, fold change>2). Moreover, lipidomic profiling demonstrated changes occurring in kidney grafts during preservation in lipid species form several classes including: PC,PA, PE and LPE.

Conclusions:The obtained results indicated that metabolites related to lipid metabolism may be of high importance in the study of ischemia/reperfusion grafts injury. The observed lipidomic alterations should be confirmed in further experiments to be considered as potential biomarkers. The results demonstrated that low invasive SPME tissue sampling, so called “chemical biopsy”, may provide adjunct diagnostic tool to standard protocol of graft quality assessment in the future.

Acknowledgment:The study was supported by grant Opus 2017/27/B/NZ5/01013 from National Science Centre. The authors would like to thank Supelco Inc. (Sigma-Aldrich Co.LLC) for SPME probes and Thermo Fisher Scientific for the access to Q-Exactive Focus orbitrap mass spectrometer.