Abstract 14296: Differential Left and Right Ventricle Response to Cold Storage Followed by Reperfusion in Heart Transplantation

Abstract

Introduction: In heart transplantation, the supply of donor hearts is contributed by the short tolerable preservation period with risk for primary graft dysfunction. Understanding the differential biological responses to preservation between the left ventricle (LV) and right ventricle (RV) may provide critical insights. Methods: Murine donor hearts were infused with cold HTK solution and stored on ice for 0h, 4h and 8h followed by 90minutes perfusion with Krebs Buffer. The LV and RV were collected at the end of reperfusion for gene expression and protein analysis by RNA-sequencing and western blot. Results: Differential gene expression analysis showed that RV has 1092 upregulated genes and 291 downregulated genes compared to LV after cold storage followed by perfusion. GO analysis show that gene sets related to immune response (padj=7e-27), cell responses to interferon-beta (padj=8.90e-19) were enriched in RV upregulated genes (figure). We also confirmed the upregulation of immune response genes such IL1-β, Myd88 by qPCR and western blot. Moreover, we found that active β-catenin, a potential upstream regulator of IL1- β, also upregulated in RV. Wnt/β-catenin downstream target genes were also enriched in human donor RVs during prolonged preservation. Importantly, donor hearts from murine Myd88-/- showed reduced differences in the transcriptome of the LV vs RV (figure) and demonstrated improved heart function after prolonged cold storage with reperfusion. Conclusions: The RV demonstrates more extensive inflammatory response to storage compared to the LV. Selective upregulation of Wnt/β-catenin signaling in the RV may be important for enhancing this inflammatory response to preservation. Deficiency of MyD88 mediated innate immune signaling improved cardiac contractility after prolonged preservation and likely have important clinical implications for transplantation.