Does oxygen supply improve graft viability in liver preservation?

Area of Science:

• Transplantation Biology
• Organ Preservation
• Biomedical Engineering

Background:

• Liver transplantation outcomes have improved, but graft viability and preservation time remain critical challenges.
• The liver's high sensitivity to anoxia necessitates enhanced preservation strategies.
• Current preservation solutions require optimization for extended graft survival.

Purpose of the Study:

• To evaluate the efficacy of an oxygen-carrying agent, pyridoxalated hemoglobin-polyoxyethylene conjugate (PHP), in liver preservation solutions.
• To compare the performance of a PHP-enriched solution (PHP+UW) against a standard UW solution.
• To assess the impact of PHP on liver graft viability under different preservation conditions.

Main Methods:

• A novel preservation solution (PHP+UW) was formulated with specific concentrations of hemoglobin and hydroxyethyl starch.
• Rat livers were preserved using either simple static storage or continuous perfusion at 4°C for 24 or 48 hours.
• Key parameters including perfusate biochemistry, hepatic mitochondrial function, tissue ATP levels, and histology were analyzed.

Main Results:

• The PHP+UW solution exhibited approximately 10 times higher oxygen-carrying capacity than the UW solution at 4°C.
• Oxygen consumption during perfusion was significantly higher with PHP+UW compared to UW.
• Hepatic mitochondrial function and ATP levels were better preserved with perfusion and the PHP+UW solution, particularly at 48 hours.

Conclusions:

• Pyridoxalated hemoglobin-polyoxyethylene conjugate (PHP) effectively enhances oxygen delivery to liver grafts.
• The use of PHP in preservation solutions improves graft viability, especially under prolonged preservation times.
• PHP represents a promising strategy for extending the safe preservation window in liver transplantation.