Role of saccharides on lung preservation

Saccharides are considered to play a role as osmotic impermeants and serve as an energy source for the organ during ischemia. However, previous studies on the effectiveness of saccharides on organ preservation have yielded conflicting results. We compared the preservative effects of a monosaccharide (glucose), disaccharides (trehalose, maltose, sucrose), and a trisaccharide (raffinose) to investigate whether the effects of saccharides on lung preservation depend on their molecular weight, energy-level maintenance, and cytoprotective effects.

We used an ex vivo rat lung model using homologous blood as the perfusate. In the fresh group, the lungs were reperfused immediately after flush. In the other groups, the lungs were flushed with one of the solutions containing glucose, trehalose, maltose, sucrose, or raffinose and preserved for 14 hours.

The results of the trehalose group were comparable to those of the fresh group. The glucose, maltose, and raffinose groups showed significantly higher levels of shunt fraction, pulmonary artery pressure, and peak inspiratory pressure compared with the fresh and trehalose groups. There were no differences among the groups in the levels of total adenine nucleotides, adenosine triphosphate of the lung after flush, and preservation. However, after reperfusion, levels of total adenine nucleotides became significantly lower in the glucose, sucrose, maltose, and raffinose groups. Ultrastructural examination revealed endothelial cell injury in the glucose, sucrose, maltose, and raffinose groups.

These results show that the effects of saccharides may depend on their cytoprotective effect rather than on impermeant activity or energy-level maintenance of the preserved lung. Trehalose proved to be superior to the other saccharides.