Enhancing Heart Transplantation: Utilizing Gas-Loaded Nanocarriers to Mitigate Cold/Hypoxia Stress

Gas-loaded nanocarriers (G-LN) show promise in improving heart transplantation (HTx) outcomes. Given their success in reducing cell death during normothermic hypoxia/reoxygenation (H/R) in vitro, we tested their integration into cardioplegic solutions and static cold storage (SCS) during simulated HTx. Wistar rat hearts underwent four hours of SCS with four G-LN variants: O₂- or N₂-cyclic-nigerosyl-nigerose-nanomonomers (CNN), and O₂- or N₂-cyclic-nigerosyl-nigerose-nanosponges (CNN-NS). We monitored physiological-hemodynamic parameters and molecular markers during reperfusion to assess cell damage/protection. Hearts treated with nanomonomers (N₂-CNN or O₂-CNN) showed improvements in left ventricular developed pressure (LVDP) and a trend towards faster recovery of the rate pressure product (RPP) compared to controls. However, nanosponges (N₂-CNN-NS or O₂-CNN-NS) did not show similar improvements. None of the groups exhibited an increase in diastolic left ventricular pressure (contracture index) during reperfusion. Redox markers and apoptosis/autophagy pathways indicated an increase in Beclin 1 for O₂-CNN and in p22phox for N₂-CNN, suggesting alterations in autophagy and the redox environment during late reperfusion, which might explain the gradual decline in heart performance. The study highlights the potential of nanomonomers to improve early cardiac performance and mitigate cold/H/R-induced stunning in HTx. These early improvements suggest a promising avenue for increasing HTx success. Nevertheless, further research and optimization are needed before clinical application.