Metabolic and transcriptomic insights into temperature controlled hypothermic preservation of human donor hearts

Abstract

Background

Heart transplantation (HT) is the gold standard for end-stage heart disease. Donor heart preservation is an important factor that influences post-transplant success. Recently, temperature-controlled storage has demonstrated reduced primary graft dysfunction compared to standard cold storage though mechanisms are poorly understood. We hypothesized that alterations in gene expression and metabolomics offer insight into improved outcomes observed with temperature-controlled storage.

Methods

We conducted a comprehensive study to investigate the metabolic and transcriptomic responses of donor hearts preserved for 6 hours using a temperature-controlled hypothermic preservation (TCHP) system compared to conventional static cold storage (SCS). Metabolic assessments were carried out using high-resolution ¹H and ³¹P nuclear magnetic resonance (NMR), and liquid chromatography/mass spectrometry (LC-MS) analysis on tissues obtained from various cardiac regions. Lactate, alanine, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), nicotinamide adenine dinucleotide (NAD), reduced nicotinamide adenine dinucleotide (NADH), phosphocreatine, and inorganic phosphate were measured, and metabolite ratios were calculated. Transcriptomic profiling was conducted using high throughput RNA sequencing followed by bioinformatic analysis to explore gene expression changes associated with different preservation methods.

Results

Metabolic analyses revealed largely similar profiles between hearts preserved with TCHP and SCS. Energy metabolite ratios were comparable between preservation methods. Transcriptomic analysis unveiled a high correlation between preservation methods but also showed differential gene expression in energy metabolism and inflammation/immune-related pathways.

Conclusions

Our study demonstrates that TCHP maintains similar high-energy phosphate reserves to SCS but leads to alterations in gene expression of several metabolic and immunomodulatory pathways. These findings may offer important insight into reduced primary graft dysfunction observed in TCHP- hearts.