Abstract: TH-PO293

Ischaemic Preconditioning of the Kidney: Total RNA Sequencing and Ingenuity Pathway Analysis

Session Information

Category: Acute Kidney Injury

  • 001 AKI: Basic

Authors

  • Foxwell, David A., Cardiff University, Cardiff, United Kingdom
  • Khalid, Usman, University Hospital of Wales, Cardiff, United Kingdom
  • Andrews, Robert, Cardiff University, Cardiff, United Kingdom
  • Pino-Chavez, Gilda, Cardiff University, Cardiff, United Kingdom
  • Chavez, Rafael E, University Hospital of Wales, Cardiff, United Kingdom
  • Bowen, Timothy, Cardiff University, Cardiff, United Kingdom
  • Fraser, Donald, Cardiff University, Cardiff, United Kingdom
Background

Ischemia-Reperfusion Injury (IRI) is a common cause of Acute Kidney Injury (AKI). Clinical trials and animal models shows that Ischemic Preconditioning (IPC), delivered directly (to the tissue) or indirectly (to other tissues), may confer protection. However, reported efficacy is variable, and development of IPC as a therapy is hampered by the current lack of detailed mechanistic understanding. The purpose of the current study was to establish the main IPC response pathways in the protected kidney, and the extent of similarity between direct and indirect IPC.

Methods

Stepwise variation in warm ischemic time was used to develop moderate AKI in the rat (defined as Creatinine ≥1.5 x sham baseline creatinine; negative control) and pulsatile, continuous, direct and indirect IPC approaches were systematically compared.

Results

Optimum benefit was observed with direct pulsatile IPC and indirect aortic IPC. Subsequently, an unbiased transcriptomic profiling of whole kidney was performed using RNA-Sequencing in animals treated with these optimum direct and indirect approaches. Six animals were compared per experimental group (n=24), at a mean paired end sequencing depth of 23.2 million reads, mapping to 16.780 unique genes. Robust differences between groups were observed (IRI vs Sham; 2,193 genes differentially regulated to a Log2FC ≥1 or ≦-1 and a corrected p ≤1.0 E-04).
Ingenuity Pathway Analysis revealed upregulation of pathways linked to inflammatory response, oxidative stress and cell cycle regulation in response to IRI, and reduction in oxidative stress, inflammation and cell cycle checkpoint regulation with IPC.

Conclusion

Together, the results displayed a molecular signature of IRI consistent with previous studies and, for the first time, uncovered a detailed signature of IPC protection that was shared between direct and indirect approaches. Our data provide novel insights into the pathogenicity of IRI injury and IPC signal, highlighting possible therapeutic targets for future investigation.